Agilent 81570A User's Guide

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Agilent 81570A, 71A, 76A, 77A & 78A

Variable Optical Attenuators

User’s Guide

Notices

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No part of this doc ument may rep roduced in ( including e lectronic s torage and retrieval or translation into a foreign language) without prior agreement and written consent from Agilent Technologies Deutschland GmbH as governed by United States and international copywright laws.

Subject Matter

The material i n this document is subject to change without notice.

Agil ent Techn ologies makes no warranty of any kind with regard to this

printed materi al, including, but not limite d to, the implied warranties of merchantability and fitness for a particular purpose.

Agilent Technologies shall not be liable for errors contained herein or for incidental or consequential damages in connection with the furnishing, performance, or use of this material.

Printing History

New editions are complete revisions of the guide reflecting alterations in the functionality of the instrument. Updates are occasionally made to the guide between editions. The date on the title page changes when an updated guide is published. To find out the current revision of the guide, or to purchase an updated guide, contact your Agilent Technologies representative.

Control Serial Number: First Edition applies directly to all instruments.

Warranty

This Agilent Technologies instrument product is warranted against defects in material and workmanship for a period of one year from date of shipment. During the warranty period, Agilent will, at its option, either repair or replace products that prove to be defective.

For warranty service or repair, this product must be returned to a service facility designated by Agilent. Buyer shall prepay shipping charges to Agilent and A gilent shall pay shipping charge s to return the product to Buyer. However, Buyer shall pay all shipping charges, duties, and taxes for products returned to Agilent from another country.

Agilent warrants tha t its software and firmware designated by Agilent for use with an instrument will execute its programming instructions when properly installed on that instrument. Agilent does not warrant that the operation of the instrument, software, or firmware will be uninterrupted or error free.

Certification

Agilent Technologies Inc. certifies that this product met its published spec ifications at the ti me of ship ment from the fact ory.

Agilent Technologies further certifies that its calibration measurements are traceable to the United States National Institute of Standards and Technology, NIST (formerly the United States National Bureau of Standards, NBS ) to the extent allowed by t he Institutes’s ca libration facility, and to the calibration facilities of other International Standards Organization members.

ISO 9001:2000 Certification

Produced to ISO 9001:2000 international quality system standard as part of our objective of continually increasing customer satisfaction through improved process contr ol.

Manual Part Number

81570-90A01

Eigth Edition: 81570-90A01: September 01, 2005

Seventh Edition: 81570-90A01: July 20, 2005

Sixth Edition: 81570-90A01: December, 2004

Fifth Edition: 81570-90A01: June 28, 2004

Fourth Edition: 81570-90A01: January 31, 2003

Third Edition: 81560-90A13: October 29, 2002

Seco nd Edition : 81560-90A12: August 04, 2002

First Edition: 81560-90A11: November 2001

Limitation of Warranty

The foregoing warranty shall not apply to defects resulting from improper or inadequate m aintenance by Buyer, Buyer-suppl ied software or interfacing, unauthorized modification or mi suse, operation outside of the environmental specifications for the product, or improper site preparation or maintenance.

No other warranty is expressed or implied. Agilent Technologies specifically disclaims the implied warranties of Merchantability and Fitness for a Particular Purpose.

Exclusive Remedies

The remedies provided herein are Buyer’s sole and exc lusive remedies. Agilent Technologies shall not be liable for any direct, indirect, special, incidental, or conseq uential damages whet her based on contract, tort, or any other legal theory.

Assistance

Product maintenance agreements and other customer assistance agreements are available for Agilent Technologies products. For any assistance contact your nearest Agilent Technologies Sales and Service Office.

2 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Safety Summary

WAR N ING The WARNING sign denotes a hazard. It calls attention to a procedure, practice or the like,

Safety Summary

The following general safety precautions must be observed during all phases of operation, service, and repair of this instrument. Failure to comply with these precautions or with specific warnings elsewhere in this manual violates safety standards of design, manufacture, and intended use of the instrument. Agilent Technologies Inc. assumes no liability for the customer’s failure to comply with these requirements.

Before operation, review the instrument and manual, including the red safety page, for safety markings and instructions. You must follow these to ensure safe operation and to maintain the instrument in safe condition.

which, if not correctly performed or adhered to, could result in injury or loss of life. Do not proceed beyond a WARNING sign until the indicated conditions are fully understood and met.

CA U TI O N Optical power levels above 100 mW applied to single mode connectors can easily damage

the connector if it is not perfectly clean. Also, scratched or poorly cleaned connectors can destroy optical connectors mechanically. Always make sure that your optical connectors are properly cleaned and unscratched before connection. Refer to chapter “Cleaning Information” on page 77 on appropriate procedures for connector cleaning and inspection. However, Agilent Technologies Deutschland GmbH assumes no responsibility in case of an operation that is not compliance with the safety instructions as stated above.

Safety Symbols

The apparatus will be marked with this symbol when it is necessary for the user to refer to the instruction manual in order to protect the apparatus against damage.

Hazardous laser radiation.

Initial Inspection

Inspect the shipping container for damage. If there is damage to the container or cushioning, keep them until you have checked the contents of the shipment for completeness and verified the instrument both mechanically and electrically.

The Performance Tests give procedures for checking the operation of the instrument. If the contents are incomplete, mechanical damage or defect is apparent, or if an instrument does not pass the operator’s checks, notify the nearest Agilent Technologies Sales/Service Office.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 3

Safety Summary

WARN ING To avoid hazardous electrical shock, do not perform electrical tests when there are signs of

shipping damage to any portion of the outer enclosure (covers, panels, etc.).

WARNING You MUST return instruments with malfunctioning laser modules to an Agilent Technologies

Sales/Service Center for repair and calibration.

Line Power Requirements

The Agilent 81570A, 71A, 78A Variable Optical Attenuator modules and Agilent 81576A, 77A Variable Optical Attenuator modules with Power Control operate when installed in the Agilent 8163A and B Lightwave Multimeters, the Agilent 8164A and B Lightwave Measurement Systems, or the Agilent 8166A and B Lightwave Multichannel Systems.

Within this User’s Guide, these instruments are collectively referred to as ‘mainframes’.

Operating Environment

The safety information in your mainframe’s User’s Guide summarizes the operating ranges for the Agilent 81570A, 71A, 78A Variable Optical Attenuator modules and Agilent 81576A, 77A Variable Optical Attenuator modules with Power Control. In order for these modules to meet specifications, the operating environment must be within the limits specified for your mainframe.

Storage and Shipment

Agilent 81570A, 71A, 78A Variable Optical Attenuator modules and Agilent 81576A, 77A Variable Optical Attenuator modules with Power Control can be stored or shipped at temperatures between

-40°C and +70°C.

Protect the module from temperature extremes that may cause condensation within it.

Environmental Information

This product complies with the WEEE Directive (2002/96/EC) marking requirements. The affixed label indicates that you must not discard this electrical/ electronic product in domestic household waste.

Product Category: With reference to the equipment types in the WEEE Directive Annex I, this product is classed as a "Monitoring and Control instrumentation" product.

Do not dispose in domestic household waste.

To return unwanted products, contact your local Agilent office, or see

www.agilent.com/environment/product/ for more information.

4 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Firmware Prerequisites

For Agilent 8156x modules with a particular firmware revision to operate correctly, your Agilent 8163A/B, 8164A/B, or 8166A/B mainframe must have a V3.5, or later, firmware revision installed.

For Agilent 8157x modules with a particular firmware revision to operate correctly, your Agilent 8163A/B, 8164A/B, or 8166A/B mainframe must have a V4.0, or later, firmware revision installed.

Firmware files are provided on the OCT Support CD-ROM supplied with the instrument, and the latest firmware revisions can also be downloaded via www.agilent.com/comms/octfirmware

The firmware for A and B versions of our mainframes is not binary compatible. Make sure you select the appropriate firmware for your instrument.

NOTE • Updating mainframe firmware does not require you to update the firmware in every

hosted module. New revisions of mainframe firmware are backwards compatible with older module firmware.

• You may find it advantageous to update module firmware. To help you determine which module firmware to update, a readme file is provided with the firmware file detailing its revision history.

• If the serial number of your 8164A Lightwave Measurement System is DExxxxx339 or below, problems with writing files to the floppy disk drive may occur in rare cases. If this is the case, please contact your nearest Agilent Technologies Sales / Service Office.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 5

Firmware Prerequisites

Checking your Current Firmware Revision

8163A/B Lightwave Multimeter, 8164A/B Lightwave Measurement System, or 8166A/B Lightwave Multichannel System

To check your 8163A/B Lightwave Multimeter, 8164A/B Lightwave Measurement System, or 8166A/B Lightwave Multichannel System's firmware revision:

1 Press the Config hardkey.

2 Move to the <About Mainframe> menu option and press Enter.

3 The manufacturer, part number, instrument number, and firmware revision are listed. If

the firmware revision number is less than V3.5 for 8156x modules, or is less than V4.0 for 8157x modules, follow the Update Procedure described in the readme.txt in the root directory of the OCT Support CD-ROM supplied with the instrument to install a later firmware revision.

8157x Series Modules

To check an 8157x series, module's firmware revision:

1 Press the Config hardkey.

2 Move to the <About Modules> menu option and press Enter. You see a box displaying

the slots that have a module installed.

3 Move to the appropriate slot using the cursor key and press Enter.

4 The part number, module number, and firmware revision of the chosen module are

displayed. If the firmware revision number is less than V4.0 for 8157x modules, follow the Update Procedure described in the readme.txt in the root directory of the OCT Support CD-ROM supplied with the instrument to install a later firmware revision.

6 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

The Structure of this Manual

This manual is divided into two parts:

• Getting Started This section gives an introduction to the attenuator modules and aims to make these modules familiar to you:

– “Getting Started with Attenuator Modules” on page 15.

• Additional Information

This is supporting information of a non-operational nature, concerning accessories, specifications, and performance tests:

– “Accessories” on page 25,

– “Specifications” on page 31, and

– “Performance Tests” on page 47.

Conventions used in this manual

• Hardkeys are indicated by italics, for example, Config, or Channel.

• Softkeys are indicated by normal text enclosed in square brackets, for example, [Zoom]

or [Cancel].

• Parameters are indicated by italics enclosed by square brackets, for example, [Range Mode], or [MinMax Mode].

• Menu items are indicated by italics enclosed in brackets, for example, <MinMax>, or <Continuous>.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 7

The Structure of this Manual

8 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Table o f Contents

Table of Contents

Safety Summary 3

Safety Symbols 3 Initial Inspection 3 Line Power Requirements 4 Operating Environment 4 Storage and Shipment 4

Firmware Prerequisites 4

Checking your Current Firmware Revision 6

8163A/B Lightwave Multimeter, 8164A/B Lightwave Measurement System, or 8166A/B Lightwave Multichannel System 6

8157x Series Modules 6

The Structure of this Manual 7

Conventions used in this manual 7

Getting Started with Attenuator Modules 15

What is an Attenuator? 17

Installation 17 Variable Optical Attenuator Front Panels 18

Front Panel Controls and Indicators 19

Typical Use Models 21

Optical Output 23

Angled and Straight Contact Connectors 23

Accessories 25

Modules and Options 27 Modules 28 User’s Guides 28 Connector Interfaces and Other Accessories 29

Specifications 31

Definition of Terms 33

Attenuation 34 Attenuation flatness 34 Attenuation range 35

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 9

Table of Contents

Attenuation setting mode 35 Attenuation uncertainty 35 Constant operating conditions 35 Insertion loss 36 Insertion loss flatness 36 Maximum Input Power 36 Operating temperature 37 Polarization Dependent Loss (PDL) 37 Polarization Extinction Ratio(PER) 37 Power setting mode 37 Relative power meter uncertainty 37 Repeatability (of attenuation or total loss) 38 Resolution 38 Return Loss 38 Settling Time 39 Shutter Isolation 39 Spectral ripple 39 Total loss 40 Transition speed 40 Wavelength Range 40

Specifications 41

Performance Tests 47

Required Test Equipment 48 Performance Test Procedure 50

Insertion Loss Test 51 Accuracy test 53 Repeatability Test 54 Power Setting Repeatability Test 54 Wavelength Flatness Test

(Not applicable to 81578A) 55 Return Loss Test

(Not applicable to 81578A) 56 Polarization Dependent Loss (PDL) Test -

Scanning Method (Not applicable to 81578A) 57

Polarization Dependent Loss (PDL) Test Mueller Method (Not applicable to 81578A) 59

10 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Table of Contents

Cleaning Information 77

Safety Precautions 79 Why is it important to clean optical devices? 80 What materials do I need for proper cleaning? 80

Standard Cleaning Equipment 80

Dust and shutter caps 81 Isopropyl alcohol 81 Cotton swabs 81 Soft tissues 82 Pipe cleaner 82 Compressed air 82

Additional Cleaning Equipment 83

Microscope with a magnification range about 50X up to 300X 83 Ultrasonic bath 83 Warm water and liquid soap 84 Premoistened cleaning wipes 84 Polymer film 84 Infrared Sensor Card 84

Preserving Connectors 85 Cleaning Instrument Housings 85 General Cleaning Procedure 86

How to clean connectors 86 How to clean optical head adapters 87 How to clean connector interfaces 88 How to clean bare fiber adapters 89 How to clean lenses and instruments with an optical glass plate 89 How to clean instruments with a fixed connector interface 90 How to clean instruments with a physical contact interface 90 How to clean instruments with a recessed lens interface 92 How to clean optical devices which are sensitive to mechanical stress

and pressure 92 How to clean metal filters or attenuator gratings 93

Additional Cleaning Information 94

How to clean bare fiber ends 94 How to clean large area lenses and mirrors 94

Other Cleaning Hints 96

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 11

Table of Contents

12 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

List of Figures

Figure 1 Agilent 81576A/77A Optical Attenuators with Power Control . . . . . . 7

Figure 2 Agilent 81570A Attenuator with Straight Connector . . . . . . . . 8

Figure 3 Agilent 81571A Attenuator with Angled Connector . . . . . . . . 8

Figure 4 Agilent 81578A Multimode Attenuator with Straight Connector. . . . . . 9

Figure 5 Agilent 81576A High-power Attenuator with Power Control and Straight Connector . 10 Figure 6 Agilent 81577A High-power Attenuator with Power Control and Angled Connector . 10

Figure 7 Angled and Straight Contact Connector Symbols . . . . . . . . . 13

Figure 8 Mainframes, Variable Optical Attenuator Modules, and Options. . . . . . 17

Figure 9 Insertion Loss Reference . . . . . . . . . . . . . . 40

Figure 10 Insertion Loss Test . . . . . . . . . . . . . . . . 41

Figure 11 Return Loss Reference Setup for SM attenuators . . . . . . . . . 45

Figure 12 Return Loss Test Setup for SM attenuators . . . . . . . . . . 45

Figure 13 PDL Test Setup - Scanning Method for SM attenuators . . . . . . . 47

Figure 14 PDL Reference Setup for SM attenuators. . . . . . . . . . . 49

Figure 15 PDL Test Setup - Mueller method . . . . . . . . . . . . 51

Figure 16 Relative Power Meter uncertainty Setup for SM attenuators . . . . . . 53

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 13

List of Figures

14 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Getting Started with Attenuator Modules

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 15

Getting Started with Attenuator Modules

CAUTION Optical power levels above 100 mW applied to single mode connectors can easily damage

This chapter describes the:

• Agilent 81570A, 81571A VOA modules,

• Agilent 81578A Multimode VOA and the

• Agilent 81576A and 81577A VOA modules with power control

16 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

What is an Attenuator? Getting Started with Attenuator Modules

What is an Attenuator?

Agilent 8157x Variable Optical Attenuators attenuate and control the optical power of light in single and multimode optical fibers. They allow you to set the attenuation factor and/or power level manually, or via the host instrument’s GPIB interface.

Agilent 81576A and 81577A attenuators include power control functionality that allows you to set the output power level of the attenuator. When power control mode is enabled, the module automatically corrects for power changes at the input so that the output power level set by the user is maintained. See Figure 1 on page 17.

Installation

Agilent 8157xA Variable Optical Attenuators are front-loadable modules for the Agilent 8163A/B Lightwave Multimeter, 8164A/B Lightwave Measurement System, and 8166A/B Lightwave Multichannel System, collectively referred to as ‘mainframes’.

An Agilent 81570A, 71A or 78A module occupies one slot, while an Agilent 81576A or 77A module occupies two slots.

For a description of how to install your module, refer to “How to Fit and Remove Modules” in the Installation and Maintenance chapter of your mainframe’s User’s Guide.

81576A / 81577A

input

Figure 1 Agilent 81576A/77A Optical Attenuators with Power Control

attenuator

control

loop

power

meter

out put

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 17

Getting Started with Attenuator Modules What is an Attenuator?

Variable Optical Attenuator Front Panels

Agilent 81570A

81570A

Figure 2 Agilent 81570A Attenuator with Straight Connector

Agilent 81571A

Figure 3 Agilent 81571A Attenuator with Angled Connector

81571A

18 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

What is an Attenuator? Getting Started with Attenuator Modules

Agilent 81578A

81578A

MMF 50um

Figure 4 Agilent 81578A Multimode Attenuator with Straight Connector

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 19

Getting Started with Attenuator Modules What is an Attenuator?

Agilent 81576A

81576A

Figure 5 Agilent 81576A High-power Attenuator with Power Control and Straight Connector

Agilent 81577A

81577A

Figure 6 Agilent 81577A High-power Attenuator with Power Control and Angled Connector

20 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

What is an Attenuator? Getting Started with Attenuator Modules

Front Panel Controls and Indicators

The front panel contains a push button to switch the shutter open/closed, and a LED that indicates the state of the shutter. If the shutter is “open”, the LED shows “enable”, and light can pass through the instrument.

Typical Us e Models

Brief description Agilent's 8157xA Variable Optical Attenuators are instruments that attenuate and control

the optical power level of light in single and multimode optical fibers. As plug-in modules for Agilent's Lightwave Multichannel platform (8163A/B, 8164A/B, 8166A/B) they allow you to set the attenuation factor and/or power level manually, or remotely via a common computer interface. Their high accuracy combined with their flexibility make them ideal as test and measurement equipment for the modern telecommunication industry.

Modular Design for Multichannel Platform Agilent's 8157xA variable optical attenuators are a family of plug-in modules for Agilent's

Lightwave Multichannel Platform 8163A/B, 8164A/B and 8166A/B. The attenuator modules 81570A, 81571A, 81578A occupy one slot, while modules 81576A and 81577A occupy two slots. The Agilent 8166A/B Lightwave Multichannel System with its 17 slots can host up to 17 single slot modules (such as the 81570A attenuators) or up to 8 dual slot modules, (such as the 81577A attenuators).

Variable Optical Attenuators Agilent's 81570A, 81571A and 81578A are small and cost effective attenuator modules

with high resolution for single-wavelength applications. Once you have entered the operating wavelength, the instrument automatically applies the appropriate corrections. Various calibration features allow you to set a reference power so that both the attenuation and the power level, relative to the reference power, can be set and displayed in the user interface. An integrated shutter can be used for protection purposes or to simulate channel drops.

Agilent's 81570A and 81571A have excellent wavelength flatness and can handle high input power levels. These features, combined with low insertion loss, allow you to use these modules for characterizing EDFAs and Raman amplifiers, as well for other multi-wavelength applications such as DWDM transmission system testing. They include the reference power functionality and an integrated shutter.

Agilent's 81578A modular attenuators are available for multimode applications with fiber interface option for 50µm (#050) and 62.5µm (#062).

Attenuators with Power Control Agilent's 81576A and 81577A attenuators have the power control functionality combined

with the high-power handling capability and excellent wavelength flatness required for DWDM applications.

To set the the total power level of a multi-wavelength signal, it is necessary to determine the convolution of the signal’s spectrum against the sensitivity of the photodiode over wavelength. An enhanced calibration feature allows you to set the integrated power of the DWDM signal against a known spectrum.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 21

Getting Started with Attenuator Modules What is an Attenuator?

Calibration Processes Comprehensive offset functionality in the firmware enhances the calibration of the optical

path in various test set-ups. There is an offset for the attenuation factor, and an independent offset for the output power level, to calibrate for losses due to the patch cords and connectors. Additionally, wavelength and offset value pairs can be stored in a table to compensate for wavelength dependent effects in the optical path of the set-up. This allows you to set the optical power level at your Device Under Test.

Calibration is even easier and more convenient if the reference powermeter and the attenuator are hosted by the same mainframe: All power related offsets can be determined by a firmware function that reads a value from the reference powermeter. The difference between the power value read by the reference powermeter and the actual value of the attenuator is automatically stored as the offset.

22 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Optical Output Getting Started with Attenuator Modules

Optical Output

Angled and Straight Contact Connectors

Agilent 81570A Variable Optical Attenuator modules and 81576A Variable Optical Attenuator modules with Power Control are designed for straight connector interfaces.

Agilent 81571A Variable Optical Attenuator modules and 81577A Variable Optical Attenuator modules with Power Control are designed for angled connector interfaces.

The Agilent 81578A (with option 050 or 062) Variable Optical Attenuator modules are designed for straight (FC/PC) multimode connector.

The inclusion of an angled contact connector is not optionable, and depends on the module part number.

Angled contact connectors help you to control return loss, since reflected light tends to reflect into the cladding, reducing the amount of light that reflects back to the source.

CAUTION If the contact connector on your instrument is angled, you can only use cables with angled

connectors with the instrument.

Angled Contact

Connector Symbol

Figure 7 Angled and Straight Contact Connector Symbols

Figure 7 shows the symbols that tell you whether the contact connector of your attenuator module is angled or straight. The angled contact connector symbol is colored green.

You should connect straight contact fiber end connectors with neutral sleeves to straight contact connectors, or connect angled contact fiber end connectors with green sleeves to angled contact connectors.

NOTE You cannot connect angled non-contact fiber end connectors with orange sleeves directly

to the instrument.

See “Accessories” on page 25 for further details on connector interfaces and accessories.

Straight Contact

Connector Symbol

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 23

Getting Started with Attenuator Modules Optical Output

24 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Accessories

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 25

Accessories

Agilent 8157xA Variable Optical Attenuator modules are available in various configurations for the best possible match to the most common applications.

This chapter describes the options and accessories available for the:

• Agilent 81570A, 81571A VOA modules,

• Agilent 81578A VOA modules for multimode applications; and the

• Agilent 81576A and 81576A VOA modules with power control.

26 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Modules and Options Accessories

Modules and Options

Figure 8 shows all the options that are available for Agilent 8157xA Variable Optical Attenuator modules, and the instruments that support these modules.

Agilent 8164A or B Lightwave Measurement System

Optical Attenuators for Straight Contact Interface

Agilent 81570A (single slot) Optical Attenuator

Agilent 81578A (single slot) Optical Attenuator for multi-mode applications. # 050: 50 µm fiber interface # 062: 62.5 µm fiber interface

Agilent 81576A VOA (dual slot) Optical Attenuator with Power Control

Variable Optical Attenuator Straight Contact Interface

Agilent 8163A or B

Lightwave Multimeter

Variable Optical Attenuator with SMF pigtail 2m length

FC/APC

Variable Optical Attenuator Angled Contact Interface

Agilent 8166A or B Lightwave Multichannel System

Optical attenuators for Angled Contact Interface

Agilent 81571A (single slot) Optical Attenuator.

Agilent 81577A (dual slot) Optical Attenuator with Power Control.

Connector Interfaces

81000 FI FC/PC/SPC 81000 HI E-2000 81000 KI SC/PC/SPC 81000 SI DIN 47256 81000 VI ST

8157xA - OC - ACCS

8157xA QC - STRGT

Connector Interface for straight connectors

8157xA QC - ANGLED

Connne ctor Interface f or angled connectors

Connector Interfaces

81000 HI E2000 APC 81000 KI SC/APC 81000 NI FC/APC 81000 SI DIN 4108.6

Figure 8 Mainframes, Variable Optical Attenuator Modules, and Options

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 27

Accessories Modules

Modules

Agilent 8157xA Modular Attenuator can be hosted by:

• Agilent 8163A and Agilent 8163B Lightwave Multimeters,

• Agilent 8164A and Agilent 8164B Lightwave Measurement Systems,

• Agilent 8166A and Agilent 8166B Lightwave Multichannel Systems.

User’s Guides

Description Part No.

Agilent 8157xA Modular Attenuator User’s Guide (English). 81570-90A01 Agilent 8163A/B Lightwave Multimeter, Agilent 8164A/B Lightwave Mea-

surement System, & Agilent 8166A/B Lightwave Multichannel System User’s Guide.

Agilent 8163A/B Lightwave Multimeter, Agilent 8164A/B Lightwave Measurement System, & Agilent 8166A/B Lightwave Multichannel System Programming Guide.

08164-90B14

08164-90B63

Connector Interfaces and Other Accessories

CAUTION Optical power levels above 100 mW applied to single mode connectors can easily damage

28 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Connector Interfaces and Other Accessories Accessories

81570A, 81578A and 81576A

Variable Optical Attenuator Modules

81571A and 81577A

Variable Optical Attenuator Modules

If you want to use straight connectors (such as FC/PC, DIN, SC or ST) to connect to the instrument, you must do the following:

1 Attach your connector interface to the interface adapter.

See Figure 8 for a list of the available connector interfaces.

2 Connect your cable.

If you want to use angled connectors (such as FC/APC or SC/APC) to connect to the instrument, you must do the following:

1 Attach your connector interface to the interface adapter.

See Figure 8 for a list of the available connector interfaces.

2 Connect your cable.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 29

Accessories Connector Interfaces and Other Accessories

30 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Specifications

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 31

Specifications

Agilent 81570A, 81571A VOA modules for high-power applications, Agilent 81578A VOA for multimode applications and Agilent 81576A and 81577A VOA modules with power control for high-power applications, are all produced to the ISO 9001 international quality system standard as part of Agilent Technologies’ commitment to continually increasing customer satisfaction through improved quality control.

Specification: describes a guaranteed product performance that is valid under the specified conditions. Specifications are based on a coverage factor of 2 (unless otherwise stated), corresponding to a level of confidence of >95.4%.

Typical v alu e: a characteristic describing the product performance that is usually met but that is not guaranteed.

Generally, all specifications apply after warm-up, for the stated operating conditions and measurement settings, with the attenuator set to the source wavelength, for transmission from input port to output port, after settling, at uninterrupted line voltage.

Because of the modular nature of the instrument, these performance specifications apply to these modules rather than the mainframe unit.

CAUTION Optical power levels above 100 mW applied to single mode connectors can easily damage

32 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Definition of Terms Specifications

Definition of Terms

This section defines terms that are used both in this chapter and “Performance Tests” on page 47.

Measurement principles are indicated. Alternative measurement principles of equal value are also acceptable.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 33

Specifications Definition of Terms

Attenuation

Difference (in dB) between total loss (with any attenuation setting) and insertion loss (i.e. with attenuation set to zero) of the attenuator.

Attenuation flatness

The change of the Attenuation over wavelength at any arbitrary but fixed displayed attenuation and fixed wavelength setting of the attenuator. The attenuation flatness is ± half the maximum span over wavelength, expressed in dB.

Attenuation flatness does not include Spectral ripple.

Conditions: Wavelength setting as specified. Temperature range, input polarization as specified. Constant operating conditions. Other conditions as specified.

Measurement: With tunable laser source, polarization scrambler (if applicable), and optical power meter.

NOTE Attenuation flatness does not include insertion loss flatness per definition.

Measurement: With an Erbium-Doped Fiber Amplifier to apply the necessary input power, tunable laser source, and optical power meter to probe the wavelength dependence of the attenuation drift.

34 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Definition of Terms Specifications

Attenuation range

Attenuation range that can be set at the attenuator and for which the specifications apply (if not differently stated).

Attenuation setting mode

Operating mode where the user sets the desired attenuation. The power control function (if available) is deactivated in this mode (see also power setting mode).

NOTE This operating mode is applicable to attenuators with power control only.

Attenuation uncertainty

The maximum possible difference (in dB) between the displayed Attenuation and actual

Attenuation.

Conditions: Attenuator set to the wavelength of the source. Input polarization, temperature

range, maximum power and input mode (multimode attenuators only) as specified. Other conditions as specified.

Measurement: With Fabry-Pérot laser source of applicable wavelength, polarization scrambler (if applicable), and optical power meter.

NOTE When using a polarized source, the attenuation uncertainty increases by ± half the

specified polarization dependent loss of the attenuator (if specified).

Constant operating conditions

This generally includes constant values of temperature, humidity, wavelength, input power level, polarization state and mode distribution (for multimode attenuators), if the quantity is not explicitly subject to variation.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 35

Specifications Definition of Terms

Insertion loss

Specifies the Tota l lo ss at a displayed attenuation of 0 dB

Conditions: Temperature range, wavelength range, source polarization input polarization, input mode (multimode attenuators only) as specified.

Measurement: With Fabry-Pérot Laser Source, polarization controller (if applicable) and power meter, using high quality connectors in perfect optical condition.

NOTE Insertion loss includes the loss of one additional connector pair.

Insertion loss flatness

The change of the insertion loss over wavelength. The insertion loss flatness is ± half the span between the maximum and minimum insertion loss, expressed in dB. Insertion Loss flatness does not include spectral ripple.

Conditions: Constant operating conditions. Fixed wavelength setting of attenuator. Input polarization, input mode (multimode attenuators only) as specified and constant. Excluding wavelengths of water absorption lines.

Measurement: With tunable laser source, polarization scrambler (if applicable), power meter, using high quality connectors in perfect optical condition. Attenuator set to 0 dB.

Maximum Input Power

The maximum input power level that can be applied to the attenuator without permanent change to its characteristics.

NOTE For input powers > 20 dBm, clean connectors in good condition are vital to avoid thermally

induced fiber damage.

36 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Definition of Terms Specifications

Operating temperature

The range of ambient temperatures of the mainframe hosting the attenuator module for which the specifications apply.

Polarization Dependent Loss (PDL)

The dependence of the total loss on the input polarization state, expressed as the full difference (in dB) between the highest and the lowest total loss.

Conditions: Temperature range, input mode (multimode attenuators only) as specified.

Measurement: Using high quality connectors in perfect optical condition.

NOTE PDL is a peak-to-peak value.

Polarization Extinction Ratio(PER)

The ratio of optical power in the slow axis of the polarization maintaining fiber to the optical power in the fast axis.

Conditions: Input power level; temperature, humidity constant; other conditions as in the Specifications; polarized light with TE mode injected in the slow axis of the polarization maintaining fiber of the attenuator.

Measurement: with ASE source and crossed-polarizer method.

Power setting mode

Operating mode where the user sets the desired output power. The power control function of the attenuator automatically adjusts the attenuation to get the set output power (see also attenuation setting mode).

NOTE This operating mode is applicable to attenuators with power control only.

Relative power meter uncertainty

When changing the output power of the attenuator, the relative power meter uncertainty is the maximum error of the displayed output power ratio to the actual output power ratio. This uncertainty is caused by the internal power meter's nonlinearity and noise and by errors in the sensing hardware, expressed as ± half the span of all possible errors with an offset due to the noise level of the power meter. Symbol RU.

Conditions: Reference power level 1mW, wavelength and polarization state constant; power limitations as in the Specifications; zeroing prior to measurement.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 37

Specifications Definition of Terms

Measurement: The nonlinearity is calculated using the displayed power ratio D2 / D1 and the corresponding actual power ratio P2 /P1:

The relative power meter uncertainty is then calculated using:

RU is then expressed in dB and the offset is expressed in pW.

NOTE This operating mode is applicable to attenuators with power control only.

NOTE Absolute power accuracy attainable with the help of an external optical power meter.

Repeatability (of attenuation or total loss)

Specifies the uncertainty in reproducing the total loss (or attenuation) after randomly changing and re-setting the attenuation. The repeatability is defined as ±2 x StDev where StDev (or total loss values) A

Conditions: Constant operating conditions. Operating in power setting mode requires zeroing prior to measurement (attenuators with power control only).

is the standard deviation over the (repeated) actual attenuations

act

Resolution

The minimum addressable and displayable attenuation steps.

(

Aact

Return Loss

Ratio between incident power and reflected power, expressed in dB. Applicable to both attenuator ports, with the respective second port terminated (zero reflectance).

Conditions: Jumper cables with high quality connectors in perfect optical condition on both attenuator ports.

38 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Definition of Terms Specifications

Measurement: With return loss meter and non-coherent source of applicable wavelength.

NOTE The measurement result includes internal reflections in the attenuator, such as reflections

from both attenuator ports and, if the shutter is closed, reflection from the shutter.

Settling Time

Maximum time needed to change the attenuation by a specified step, from the beginning until the end of the change.

NOTE Settling time excludes the time needed for the interpretation of the command and for the

internal communication between the mainframe and the attenuator module.

Shutter Isolation

Ratio between transmitted powers with open and with closed shutter, at a displayed attenuation of 0 dB, expressed in dB.

NOTE For another displayed attenuation, the isolation is increased by the attenuation.

Spectral ripple

Spectral ripple is a periodic change of the total loss as a function of the input wavelength when using a coherent light source. The spectral ripple is ± half the span between the maximum and the minimum total loss, expressed in dB.

Spectral ripple does not include attenuation flatness or insertion loss flatness.

Conditions: Constant operating conditions. Linewidth as specified.

NOTE Spectral ripple results from interference between the passing wave and spurious internal

reflections.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 39

Specifications Definition of Terms

Total loss

The change of power level after inserting the attenuator between two connectorized patchcords, at an arbitrary attenuation setting, expressed in dB. Its value TL can be calculated from:

where:

Pa = power measured at the end of the two patchcords.

Pb = power measured after the insertion of the attenuator.

Conditions: Patchcord cables with high quality connectors in perfect optical condition on

both attenuator ports.

NOTE The total loss depends on the attenuation setting.

NOTE Total loss includes the loss of one additional connector pair.

Transition speed

Specifies the settable attenuation change rate of the attenuator.

Wavelength Range

The range of wavelengths that can be set at the attenuator and for which the specifications apply (if not differently stated).

40 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Specifications Specifications

Specifications

The following Specifications tables are provided:

•“Variable optical attenuator modules for single mode applications” on page 43, which describes the Agilent 81570A, Agilent 81571A.

•“Variable optical attenuator modules with power control for single mode applications” on page 45, which describes the Agilent 81576A and Agilent 81577A.

•“Variable optical attenuator modules for multimode applications” on page 46, which describes the Agilent 81578A.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 41

Specifications Specifications

- this page deliberately blank -

42 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Specifications Specifications

Table 1 Variable optical attenuator modules for single mode applications

81570A 81571A

Connectivity

Fiber type

Wavelength range

Attentuation range

Resolution

Repeatability

Accuracy (uncertainty)

Settling time

Transition speed

Attenuation flatness

Spectral ripple

Insertion loss

Insertion loss flatness

Polarization dependent loss Polarization extinction ratio Return loss Maximum input power Shutter isolation Dimensions (H x W x D) Weight Recommended recalibration period Operating temperature Humidity Warm-up time

1, 2, 3, 4

1, 4, 6, 8

2, 4, 9, 10

1, 4,11

2, 9, 11

9, 11

straight connector versatile interface

9/125 µm SMF28 9/125 µm SMF28

angled connector

versatile interface

1200-1700 nm

0-60 dB

0.001 dB

±0.01 dB

±0.1 dB

typ. 100 ms

typ. 0.1 ... 12 dB/s

< ±0.07 dB (typ. ±0.05 dB) for 1520 nm < λ < 1620 nm

typ. ±0.10 dB for 1420 nm < λ < 1640 nm

typ. ±0.003 dB

typ. 0.7 dB excluding connectors

< 1.6 dB (typ. 1.0 dB) including connectors

typ. ±0.1 dB for 1420 nm < λ <1615 nm

< 0.08 dBpp (typ. 0.03 dBpp)

N/A

typ. 45 dB typ. 57 dB

+ 33 dBm

typ. 100 dB

75 mm x 32 mm x 335 mm (2.8" x 1.3" x 13.2")

0.9 kg

2 years

10 °C - 45 °C

Non-condensing

30 min.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 43

Specifications Specifications

Table 1 Variable optical attenuator modules for single mode applications

At constant temperature

Tem pe ra tu re w it hin 23° ± 5 K

Input power < +30 dBm; λ = 1550 nm ± 15 nm;

typical for 1250 nm <

For unpolarized light (SMF versions), or polarized light

λ < 1650 nm

with TE mode injected in the slow axis (PMF version)

Stepsize < 1 dB; for full range: typ. 6 s

Relative to reference at 0 dB attenuation

Linewidth of source > 100 MHz

l disp set to 1550 nm;attenuation ≤ 20 dB; for attenuation >20 dB:

add typ. 0.01 dB ( a [db] - 20) for 1520 nm < add typ. 0.02 dB ( a [db] - 20) for 1420 nm <

λ < 1620 nm

λ < 1640 nm

For λ= 1550 nm ± 15 nm

Add typ. 0.1 dB for λ= 1310

nm ± 15 nm

Measured with Agilent ref

erence connectors

Excluding connectors, mea sured with a broadband source.

Agilent Technologies Deut schland GmbH assumes no responsibility for damages caused by scratched or poorly cleanedconnectors.

44 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Specifications Specifications

Table 2 Variable optical attenuator modules with power control for single mode applications

81576A 81577A Connectivity straight connector, versatile interface angled connector, versatile interface Fiber type 9/125

µm SMF

Wavelength range 1250-1650 nm Attentuation range 0-60 dB Resolution 0.001 dB

Attenuation Setting Power Setting Attenuation Setting Power Setting

Repeatability

Accuracy (uncertainty) Settling time

1, 3, 4, 5

±0.010 dB ±0.015 dB

±0.1 dB ±0.1 dB

typ. 100 ms typ. 300 ms typ. 100 ms typ. 300 ms

±0.010 dB ±0.015 dB

Transition speed typ. 0.1 ... 12 dB/s Relative power meter uncertainty

Attenuation flatness

Spectral ripple

Insertion loss

Insertion loss flatness Polarization dependent loss Return loss

12, 14

Maximum input power

1, 5, 9, 10

3, 5, 12, 13

1, 5, 14

3, 12, 14

± 0.03 dB ± 200 pW

< ±0.07 dB (typ. ±0.05 dB) for 1520 nm < λ < 1620 nm

typ. ±0.10 dB for 1420 nm <

typ. ±0.003 dB

typ. 0.9 dB excluding connectors

< 1.8 dB (typ. 1.2 dB) including connectors

typ. ±0.1 dB for 1420 nm < λ < 1615 nm

< 0.10 dBpp (typ. 0.05 dBpp)

typ. 45 dB typ. 57 dB

+ 33 dBm

λ < 1640 nm

Shutter isolation typ. 100 dB Dimensions (H x W x D) 75 mm x 64 mm x 335 mm (2.8" x 2.6" x 13.2") Weight 1.3 kg Recommended recalibration period 2 years Operating temperature 10 °C - 45 °C Humidity Non-condensing Warm-up time 30 min.

At constant temperature

Output power > - 40 dBm, input power < +27 dBm,

for input power > +27 dBm add typically ±0.01 dB

Temperature within 23 °C ± 5 K,

Input power < + 30 dBm; λ = 1550 nm ± 15 nm;

typical for 1250 nm < λ < 1650 nm

For unpolarized light

Stepsize < 1 dB; for full range: typ. 6 s

Wavelength and SOP constant;

temperature constant and between 23 °C ± 5 K; λ < 1630 nm

Input power ≤ + 27 dBm, for input power > +27 dBm add ±

Relative to reference at 0 dB attenuation

λ disp set to 1550 nm; attenuation ≤ 20 dB;

for attenuation > 20 dB: add typ. 0.01 dB ( a [db] - 20) for 1520 nm < λ < 1620 nm add typ. 0.02 dB ( a [db] - 20) for 1420 nm < λ < 1640 nm

Linewidth of source ≥ 100 MHz

For λ = 1550 nm ± 15 nm

Add typ. 0.1 dB for λ = 1310 nm ± 15 nm

Measured with Agilent reference connectors

Agilent Technologies Deutschland GmbH assumes no responsibility

for damages caused by scratched or poorly cleaned connectors.

0.02 dB

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 45

Specifications Specifications

Table 3 Variable optical attenuator modules for multimode applications

81578A #050 81578A #062 Connectivity straight connector, versatile interface straight connector, versatile interface Fiber type 50/125

µm MMF 62.5/125 µm MMF

Wavelength range 700-1400 nm Attentuation range 0-60 dB Resolution 0.001 dB Repeatability

Accuracy (uncertainty)

Settling time

1, 2, 5

±0.015 dB

typ. ±0.15 dB

±0.2 dB

typ. 100 ms

Transition speed typ. 0.1 ... 12 dB/s

Insertion loss

Return loss

1, 2, 4, 5

2, 5, 7

Maximum input power

typ. 1.0 dB for NA = 0.1

2.0 dB for NA = 0.2, (typ. 1.3 dB)

typ. 27 dB

+ 27 dBm

typ. 1.0 dB for NA = 0.1

2.0 dB for NA = 0.2, (typ. 1.3 dB) typ. 3.0 dB for NA = 0.27

Shutter isolation typ. 100 dB Dimensions (H x W x D) 75 mm x 64 mm x 335 mm (2.8" x 2.6" x 13.2") Weight 0.9 kg Recommended recalibration period 2 years Operating temperature 10 °C - 45 °C Humidity Non-condensing Warm-up time 30 min.

Under constant conditions

Effective spectral bandwidth of source > 5 nm

For mode launch conditions with NA = 0.2; for every ∆NA = 0.01 add typ. ± 0.01 dB

Temperature within 20°C ± 5K and un polized light

At 850 nm ± 15 nm, 1310 nm ± 15 nm

Step size < 1 dB; for full range: typ. 6 s

The return loss is mainly limited by the return loss of the front panel connectors

Agilent Technologies Deutschland GmbH assumes no responsibility for damages caused by scratched or poorly cleaned connectors.

46 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Tests

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 47

Performance Tests Required Test Equipment

The performance tests in this section test the optical performance of the Agilent 8157xA modular Optical Switches. The complete specifications to which the instrument is tested are given in “Specifications” on page 31.

All tests can be performed without access to the interior of the instrument. The performance tests refer specifically to tests using an Agilent reference connector.

Required Test Equipment

The equipment required for the performance test is listed in Ta b l e 4 . Any equipment that satisfies the critical specifications of the equipment given in Ta b l e 4 may be substituted for the recommended models.

Table 4 Equipment Required

Instrument/Accessory Model

Lightwave Multimeter Agilent 8163A/B x x x x x x 2 x (4 slots) 8164A/B Laser Source Module FP Agilent 81654A x x x x - - 1550 nm Tunable Laser Source Module Agilent 81689A x x x x - - 81640A Power Sensor Module Agilent81634B x x x x - Interface Module Agilent 81618A x x x x x x Optical Head Agilent 81624B x x x x x x low PDL Depolarizing Filter Agilent 81000DF x x x x - HMS-10 Optical Head Adapter Agilent 81000AA x x x x x x Optical Attenuator Agilent 81561A - - x x - - 8156A #201 Return Loss Module Agilent 81612A x x x x - Reference Cable Agilent 81610CC x x x x - Polarization Controller Agilent 11896A #022 x x x x - - 8169A #022 Single Mode Fiber Agilent 81101AC x - x - - - HMS-10(s) to HMS-10(s) Single Mode Fiber Agilent 81113SC x x x x - - DIN(a) to DIN(a) Single Mode Fiber Diamond 253-117-

003L002

Single Mode Fiber Diamond 117-183-

003L002

Single Mode Fiber Diamond 253-183-

003L002 Connector interface HMS-10 Agilent 81000AI x - x - x x Connector interface FC/PC Agilent 81000FI - - - - x x N-key Connector interface FC/APC Agilent 81000NI - - - - - - R-key

Required

Characteristics

81570A

81571A

81576A

81577A

81578A # 050

81578A # 062

x x x x - - DIN(a) to HMS-10(s)

x x x x - - DIN(a) to FC/PC(a)

------FC/PC(a) to HMS-10(s)

Alternative

Models

48 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Required Test Equipment Performance Tests

Table 4 Equipment Required

Instrument/Accessory Model

81570A

81571A

81576A

81577A

81578A # 050

81578A # 062

Connector interface DIN Agilent 81000SI x x x x - DIN Feedthrough Adapter 1005-0255 - x - x - FC/PC Feedthrough Adapter 1005-0256 - - - - - HMS-10 Universal Adapter 81000UM x - x - x x FP-Source, 850nm, MM 81655A_E01 - - - - x x 81551MM FP-Source, 1310nm, SM 81655A - - - - x x 81657A Optical Head 850nm 81623B_E01 - - - - x x 81520A Mode Conditioner 81578-63201

(Note 1)

Mode Stripper, 50um 81578-63202

(Note 2)

NOTE:

1. Diamond AMCB - 180 - 000V050

----xx

----x-

Required

Characteristics

Alternative

Models

2. Service tool, only available for Agilent service centers. Not available for trade sales.

Legend: x necessary

- not applicable ooptional (a) angled physical contact (s) straight physical contact

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 49

Performance Tests Performance Test Procedure

Test Record

Results of the performance test may be tabulated on the Test Record provided at the end of the test procedures. It is recommended that you fill out the Test Record and refer to it while executing the test. Since the test limits and setup information are printed on the Test Record for easy reference, the record can also be used as an abbreviated test procedure ( if you are already familiar with the test procedure). The test Record can also be used as a permanent record and may be reproduced without written permission from Agilent Technologies. The Test Record states rejection limits for the supplementary characteristics (typical specifications).

Test Failure

If the Agilent 8157xA High Power Optical Attenuator module fails any performance test, return the instrument to the nearest Agilent Technologies Sales/Service Office for repair.

Instrument Specification

Specifications are the performance characteristics of the instrument that is certified. These specifications, listed in “Variable optical attenuator modules for single mode applications” on page 43 are the performance standards or limits against which the Agilent 8157xA can be tested.

Any changes in the specification due to manufacturing changes, design, or tracebility to the National Institute of Standards and Technology (NIST), will be covered in a manual change supplement, or revised manual. Such specifications supercede any that were previously published.

Performance Test Procedure

The performance test given in this section includes the Attenuation Repeatability Test. Perform each step in the order given, using the corresponding test equipment.

Operate the Agilent 81576A and 81577A Attenuator modules as attenuators and switch the power control loop off if not otherwise mentioned.

50 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

WARNING Make sure that all optical connections of the test setup given in the

procedure are dry and clean. DO NOT USE INDEX MATCHING OIL. Make sure that all optical connectors are undamaged.

For cleaning, use the cleaning instructions given in “Cleaning Information” on page 77.

Make sure that all optical cables of the test setup are fixed to the table so that they won't move during measurements.

Movement of the fibers during the test procedures and the quality of optical connectors affect the result of power measurements.

The environmental conditions (temperature and relative humidity) must remain constant during the test.

Insertion Loss Test

Carry out the following Insertion Loss Test at 1550 nm (81578A at 850 nm and 1310 nm) with single mode fibers using the equipment listed in Tab l e 4 on page 48. To adapt for the straight or angled contact versions of the optical switch use patchcords with appropriate connectors and suitable connector interfaces.

1. Turn the instruments on and allow the devices to warm up (20...30 min).

2. Make sure that all your connectors are clean and undamaged.

3. Connect the equipment as shown in Figure 9.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 51

Performance Tests Performance Test Procedure

Setup for MM attenuators

Figure 9 Insertion Loss Reference

Set the attenuator and the power meter to the actual wavelength of the laser source.

2 Disable the laser source, zero the power meter and select Autorange.

Display [dB].

3 Set the power meter averaging time to 500 ms. 4 Enable the laser source and set Display to Reference on the power

meter.

5 Set attenuation [a] to 0 dB and open the shutter. 6 Record the power meter reading (in dB) as Insertion Loss in the Test

Record.

7 Connect the equipment as shown in Figure 10 on page 53.

Setup for SM attenuators

52 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Setup for MM attenuators

Figure 10 Insertion Loss Test

Accuracy test

Use the same equipment and test setup as used in Figure 10 on page 53

1 Turn the instruments on and allow the devices to warm up (20 to 30

min.).

2 Make sure that all your connectors are clean and undamaged. 3 Set the attenuator and the power meter to the actual wavelength of the

laser source.

4 Disable the laser source, zero the power meter and select Autorange.

Display [dB].

5 Enable the laser source, open the shutter and set the attenuation [a] to

dB.

6 Set display to Reference on the power meter. 7 Set the attenuation [a] to the different values listed below and note the

power meter reading in the test record.

1 dB 2 dB 3 dB 4 dB 5 dB

6 dB 7 dB 8 dB 9 dB 10 dB 11 dB 12 dB 13 dB 14 dB 15 dB 25 dB 35 dB 45 dB 55 dB 60 dB

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 53

Performance Tests Performance Test Procedure

Repeatability Test

Use the same equipment and test set up as used in Figure 10.

1 Turn the instruments on and allow the devices to warm up (20..30 min). 2 Make sure that all your connectors are clean and undamaged. 3 Set the attenuator and the power meter to the actual wavelength of the

laser source.

4 Disable the laser source, zero the power meter and select Autorange.

Display [dB].

5 Enable the laser source and open the shutter. 6 Set the attenuation [a] to 1 dB, wait until it settles and set Display to

Reference on the power meter.

7 Set the attenuation [a] to any other value (e.g. 21 dB) and wait until it

settles at this value.

8 Change the attenuation [a] back to the previous value and note the

deviation in the Test Record.

9 Repeat step 3 to step 5 for the following attenuation settings:

7 dB 15 dB 24 dB 32 dB

40 dB 48 dB 54 dB 60 dB

Power Setting Repeatability Test

Use te same equipment and test setup as used in Figure 10 on page 53 without the Agilent 81634B Power Meter. The performance test can be performed at other wavelengths than 1550 nm.

1 Turn the instruments on and allow the devices to warm up (20..30 min). 2 Make sure that all your connectors are clean and undamaged. 3 Set the attenuator to the actual wavelength of the laser source and set

the averaging time to 1 sec.

4 Zero the attenuator power meter, disable the power control and Display

[dBm].

5 Enable the laser source and open the shutter. 6 Set [P

ACT

7 Set [P 8 Change [P

ACT

9 Repeat step 6 to step 8 for [P

] to 0 dBm and wait for it to stabalize. Note the reading of

SET

] in the Test Record.

] to any other value and wait for it to settle.

SET

] back to the previous value and note the deviation of

SET

] in the Test Record.

] = -25 dBm and [P

SET

] = -50 dBm.

SET

54 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Wavelength Flatness Test (Not applicable to 81578A)

Use the same test setup as used in Figure 10 on page 53 but replace the Agilent 81654A Fabry Perot Laser Source with the Agilent 81689A Tunable laser Source.

10 Turn the instruments on and allow the devices to warm up (20..30 min). 11 Make sure that all your connectors are clean and undamaged. 12 Connect the equipment as shown in Figure 10 on page 53. 13 Make sure that the power meter and tunable laser source are hosted by

the same mainframe.

14 Start the PACT application by pressing the [APPL] button on the

mainframe and selecting PACT.

15 Select the modules and the sweep parameters as follows:

l Start = 1524.0 nm

l Stop = 1576.0 nm

Step = 0.1 nm

= 0.000 dBm

max

16 Press [Reference] and in the next screen [New Ref] and start the

reference measurement.

17 Return to the setup menu by pressing [Menu] and selecting [Setup]. 18 Connect the equipment as shown in Figure 9 on page 52. 19 Set the attenuation to 15 dB. 20 Press [Measure] to start the DUT measurement. 21 After completion press [Graph] to enter the Trace Display. 22 Use the markers C and D to mark the maximum and minimum Insertion

Loss peak and note the power difference D in the Test Record.

Return Loss Test (Not applicable to 81578A)

Carry out the following Return Loss Test at 1550 nm with single mode fibers using the equipment listed in Ta b l e 4 , “Equipment Required,” on page 48. To adapt for the straight or angled contact versions of the attenuator, use patchcords with appropriate connectors and suitable connector interfaces.

1 Turn the instruments on and allow the devices to warm up (20...30 min). 2 Make sure that all your connectors are clean and undamaged.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 55

Performance Tests Performance Test Procedure

Connect the equipment as shown in Figure 11.

Figure 11 Return Loss Reference Setup for SM attenuators

Set the attenuator and the power meter to the actual wavelength of the internal laser source of the return loss meter.

5 Disable the internal laser source, cover the end of the reference cable

and zero the return loss meter.

6 Uncover the clean end of the reference cable and enable the laser

source.

7 Select the REF CAL parameter and set the reflection reference R to 14.7

dB, the default value for the return loss of the reference reflector cable 81610CC.

8 Set Display to Reference. The value read should now be 14.7 dB, the

same as the value entered for reflection reference R.

9 Select the REF AUX parameter and terminate the reference cable by

wrapping the fiber several times around a rod with a diameter around 5 mm (such as a screwdriver shaft, or a pencil).

10 Set Display to reference to set the termination parameter. 11 Remove the reference cable and reconnect the equipment as shown in

Figure 12.

Figure 12 Return Loss Test Setup for SM attenuators

Terminate the patchcord on the attenuator output by wrapping the fiber several times around a rod with a diameter around 5 mm (such as a screwdriver shaft, or a pencil). Do the same for the monitor output if applicable.

56 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

13 Set the attenuation [a] to 0 dB and note the input return loss in the Test

record.

14 Open the shutter and record the return loss in the Test Record. 15 Connect the return loss meter to the attenuator output port and

terminate the input port as described in step 12

16 You may measure the output return loss for open and closed shutter or

for other arbitrary attenuation settings as described in step 13 and step 14 .

Polarization Dependent Loss (PDL) Test Scanning Method (Not applicable to 81578A)

Carry out the following PDL Test at 1550 nm with single mode fibers using the equipment listed in Ta bl e 4 on page 48. To adapt for the straight or angled contact versions of the switch use patchcords with appropriate connectors and suitable connector interfaces.

WARNING This test is recommended for the fiber loop-type 11869A Polarization

Controller. For plate-type Polarization Controller 8169A refer to section

“Polarization Dependent Loss (PDL) Test - Mueller Method (Not applicable to 81578A)” on page 58.

1 Turn the instruments on and allow the devices to warm up (20..30 min). 2 Make sure that all your connectors are clean and undamaged.

3 Connect the equipment as shown in Figure 13

Figure 13 PDL Test Setup - Scanning Method for SM attenuators

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 57

Performance Tests Performance Test Procedure

WARNING The patchcords to and from the polarization controller and the attenuator

must not move during a measurement, or between any measurements. Use tape to fix the fibers to the table.

4 Set the attenuator to the wavelength of the laser source. 5 Enable the laser source, and open the shutter of the attenuator. 6 Display [dB] at the power meter and set Display to reference. 7 Choose the power meter Stability Application and set the parameters

as follows:

• Tot al Tim e -2 5 s ec onds

• Averaging Time -50 ms

• Wavelength -Source wavelength

• Range Mode -auto

8 Set the 11896A Polarization Controller scan rate = 4 and press

[AutoScan] to start Polarization Scrambling.

9 Press Measure at the power meter to start PDL Scanning. 10 After the mesurement press [Analysis] and [More] to get the power

readings.

11 Note the results in the Test Record.

Polarization Dependent Loss (PDL) Test Mueller Method (Not applicable to 81578A)

Carry out the following PDL Test at 1550 nm with single mode fibers using the equipment listed in Ta b le 4 on page 48. To adapt for the straight or angled contact versions of the attenuator use patchcords with appropriate connectors and suitable connector interfaces.Use the operation mode Attenuation Set

WARNING Perform this test with the plate-type 8169A Polarization Controller.

1 Turn the instruments on, and allow the devices to warm up (20...30

min).

2 Make sure that all your connectors are clean and undamaged. 3 Connect the equipment as shown in Figure 14

58 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Figure 14 PDL Reference Setup for SM attenuators

WARNING

The patchcords to and from the polarization controller and the attenuator must not move during a measurement, or between any measurements. Use adhesive tape to fix the fibers to the table.

4 Zero the power meter. Display [W]. 5 Set the attenuator and the power meter to the actual wavelength of the

source.

6 Enable the laser source and allow 5 minutes for the laser to settle. 7 Reset the polarization controller. 8 Set the polarization filter of the 8169A to maximize the signal. 9 Note the displayed angle of the polarization filter as "Linear Horizontal

Setting".

WARNING Set plates for Horizontal polarization. For the following steps the polarizer

is kept constant.

10 Set the λ/4 Retarder Plate to the same angle as the polarization filter. 11 Note the angle as λ/4 "Linear Horizontal Polarization" 12 Set the λ/2 Retarder Plate to the same angle as the polarization filter. 13 Note the angle as λ/2 "Linear Horizontal Polarization".

Determine settings for Linear Vertical, Linear Diagonal, and Right Hand Circular Polarization.

WARNING In order to get the required polarization, the λ/2 and λ/4 retarder plates

need to be set to the appropriate values. The corrected positions of the polarizer plates depend on the actual wavelength and have to be taken from Ta b l e 5 , “Retarder Settings,” on page 62.

WARNING In the case of Linear Horizontal polarized light no correction is to be made.

The table lists corrections for every 20 nm step. For wavelengths between listed values, a linear approximation should be used.

14 Get the values (possible by approximation) for the wavelength

dependent offset positions for each type of polarization from Ta b l e 5 , “Retarder Settings,” on page 62.

15 Add these values to those for Linear Horizontal polarized light.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 59

Performance Tests Performance Test Procedure

Note the calculated corrected wavelength dependent position values in the Test Record for the λ/4 Plate setting and the λ/2 Plate setting for Linear Vertical, Linear Diagonal, and Right Hand Circular Polarization.

Measure the Reference Power

17 Keep the settings from the polarizer and the λ/4 and λ/2 Retarder

Plates from step 5, step 6 and step 12 for Linear Horizontal polarized light.

18 Note the power reading as Reference Power P 19 Set the λ/4 and λ/2 Retarder Plates to the corrected wavelength

in the Test Record.

dependent positions for Linear Vertical polarized light.

20 Read the power on the power meter and note as Reference Power P

the Test Record.

21 Set the λ/4 and λ/2 Retarder Plates to the corrected wavelength

dependent positions for Linear Diagonal polarized light.

22 Note the power reading as Reference Power P 23 Set the λ/4 and λ/2 Retarder Plates to the corrected wavelength

in the Test Record.

dependent positions for Right Hand Circular polarized light.

24 Note the power reading as Reference Power P 25 Connect the equipment as shown in Figure 15

in the Test Record.

60 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Figure 15 PDL Test Setup - Mueller method

WARNING

The patchcords to and from the polarization controller and the attenuator must not move during, or between measurements. Use adhesive tape to fix the fibers to the table.

Measure the Optical Power after the Attenuator Module

26 Open the shutter of the attenuator. 27 Set the λ/4 and λ/2 Retarder Plates for Linear Horizontal polarized light. 28 Note the power reading as DUT Power P 29 Set the λ/4 and λ/2 Retarder Plates to the corrected wavelength

dependent positions for Linear Vertical polarized light.

30 Note the power displayed on the power meter as DUT Power P

Tes t R ec or d.

31 Set theλ/4 and λ/2 Retarder Plates to the corrected wavelength

dependent positions for Linear Diagonal polarized light.

32 Note the power reading as DUT Power P 33 Set theλ/4 and λ/2 Retarder Plates to the corrected wavelength

dependent positions for Right Hand Circular polarized light.

in the Test Record.

in the

34 Note the power reading as DUT Power P 35 Calculate the Mueller coefficients, the maximum and minimum

in the Test Record.

transmission and finally the Polarization Dependent Loss (PDL) as described in the Test Record.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 61

Performance Tests Performance Test Procedure

Table 5 Retarder Settings

λ/νµ

1580

1560

1540

1520

1500

Linear Vertical Linear Diagonal Right hand circular

λ/4 Plate λ/2 Plate λ/4 Plate λ/2 Plate λ/4 Plate λ/2 Plate

° 46.2° 1.7° 23.3° 42.9° -17.1°

2.5

° 45.6° 0.8° 22.9° 44.0° -16.5°

1.2

° 45.0° 0° 22.5° 45.0° -15.1°

° 44.3° -1.0° 22.0° 46.2° -13.8°

-1.4

-2.7

° 43.6° -2.0° 21.4° 47.4° -12.4°

62 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Relative Power Meter Uncertainty Test

This test applies to the Agilent 81576A and 81577A Attenuators with power control.

Carry out the following Power Meter Uncertainty Test at 1550 nm or another spwcified wavelength with single mode fibers using the equipment listed in Ta b le 4 on page 48. To adapt for the straight or angled contact versions of the attenuator use patchcords with appropriate connectors and suitable connector interfaces.

WARNING Do not turn the laser off during the measurement! Clean all connectors

carefully before you start with the measurement.

1 Turn the instruments on and allow the devices to warm up (20 to 30

min.).

2 Make sure that you perform this test in an environment with

temperature fluctuations less than ± 1°C.

3 Make sure that all your connectors are clean and undamaged. 4 Connect the equipment as shown below in Figure 16.

Figure 16 Relative Power Meter uncertainty Setup for SM attenuators

Set both attenuators to the wavelength of the source and disable them.

6 Set the attenuation [α] of 81570A reference attenuator to 55dB. 7 Set the attenuation [α] of the DUT attenuator to 0 dB. 8 Set the averaging time of the DUT attenuator power meter to 1 s. 9 Zero the reference and the attenuator power meter. 10 Enable the laser source and wait for it to stabalize (> 30 seconds). 11 Enable the attenuators. 12 Set the reference power meter to the wavelength of the source, set the

averaging time to 1 s. and display [dB]. Press [Display to Reference.

13 Set the range mode of the reference power meter to Manual. 14 On the DUT attenuator edit P Offset until the parameter P

dBm.

15 Lower P 16 Note the reference power meter reading in the Test record.

and the attenuation of the reference attenuator by 5 dB.

SET

equals 0

SET

17 Repeat step 14 and step 15 until the reference attenuator shows an

attenuation of 0 dB.

18 Perform step 14 and step 15 upward until the reference attenuator

shows 55 dB.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 63

Performance Tests Performance Test Procedure

64 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Test Re cord

Agilent High Power Optical Attenuator Performance Test Page 1 of 6

Test Facili ty:

Report No.:

Date:

Customer:

Tes t ed B y:

Model: Agilent High Power Optical Attenuator Product Number: #

Serial No. Ambient temperature

Firmware Rev. Relative humidity %

Line frequency Hz

Special Notes:

°C

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 65

Performance Tests Performance Test Procedure

Agilent High Power Optical Attenuator Performance Test

Agilent High Power Optical Attenuator Report No. Date:

Test Eq uipment

# Description Model No. Trace No. Cal. due date

1Mainframe / /

2Power Meter / /

3Laser Source / /

4 Return Loss Module / /

5 Connector Interface / /

6 Single Mode Fiber / /

7 / /

8 / /

Page 2 of 6

9 / /

10 / /

11 / /

12 / /

13 / /

14 / /

15 / /

16 / /

17 / /

18 / /

19 / /

20 / /

66 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Agilent High Power Optical Attenuator Performance Test

81570A/ 71A/ 76A/ 77A Agilent High Power Optical Attenuator Report No. Date

Insertion Loss Test

Product 81570A/71A 81576A + 81577A

Measurement Upper test limit 1.5 dB 2.0 dB

Attenuation Accuracy Test

Setting/dB Reading/dB Deviation/dB

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 25 35 45 55 60

Most positiveDeviation

Upper test limit +0.1 dB

Most negative Deviation

Lower test limit -0.1 dB

Page 3 of 6

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 67

Performance Tests Performance Test Procedure

Agilent High Power Optical Attenuator Performance Test Page 4 of 6

81570A/ 71A/ 76A/ 77A

Agilent Modular Optical Attenuator Report No. Date

Attenuation Repeatability Test

Setting / dB Deviation / dB

7 15 24 32 40 48 54 60

Maximum peak-to-peak Deviation

Upper test limit 0.02 dBpp

Power Setting Repeatability Test

Power Setting/dB Deviation/dB

0 dBm

-25 dBm

-50 dBm

Maximum peak-to-peak Deviation

Upper test limit 0.03 dBpp

Wavelength Flatness Test

Product 8157xA

Measurement Upper test limit 0.14 dBpp

Return Loss Test

Product 81570A + 81576A 81571A/77A

Attenuation Setting Shutter State Measurement Input Port Measurement Output Port Lower test limit 42 dB 54 dB

Open Closed

68 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Agilent High Power Optical Attenuator Performance Test Page 5 of 6

81570A/ 71A/ 76A/ 77A Agilent High Power Optical Attenuator Report No. Date

Polarization Dependent Loss Test - Scanning method (11896A)

Product 81570A/71A 81576A + 81577A

Attenuation Setting Maximum peak-to-peak Deviation Upper test limit 0.8 dBpp 0.10 dBpp

Polarization Dependent Loss Test - Mueller method (8169A)

Attenuation setting: dB

Polarization

Linear Horizontal Linear Vertical Linear Diagonal Right Hand Circular

Polarizer Setting deg n/a n/a n/a

λ/4 Plate Setting deg n/a n/a n/a λ/2 Plate Setting deg n/a n/a n/a

Corrected Wavelength dependent positions

Linear Horizontal Linear Vertical Linear Diagonal Right Hand Circular

Polarizer Setting n/a deg deg deg

λ/4 Plate Setting n/a deg deg deg λ/2 Plate Setting n/a deg deg deg

Measurement P

Reference Power µW µW µW µW DUT Power

µW µW µW µW

Mueller Coefficients

=(P

DUT1/PREF1

=(P

DUT1/PREF1

=(P

DUT3/PREF3

=(P

DUT4/PREF4

+ P

DUT2/PREF2

- P

DUT2/PREF2

) - m

)/2 =

= =

Minimum ans maximum Transmission

max

min

+++

++–

Product 81570A/71A 81576A + 81577A

Polarization dependent loss PDL = 10lg(Tmax/Tmin) dBpp

Upper test limit 0.8 dBpp 0.10 dBpp

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 69

Performance Tests Performance Test Procedure

Agilent High Power Optical Attenuator Performance Test

81570A/ 71A/ 76A/ 77A Agilent High Power Optical Attenuator Report No. Date

Relative Power Meter Uncertainty Test

8157xA [P

]/ dBm Reference Attenuation/dB Reference Reading 1 /dB Reference Reading 2 /dB

SET

-5

-10

-15

-20

-25

-30

-35

-40

-45

-50

-55 Maximum peak-to-peak deviation

Upper test limit 0.06 dBpp

Page 6 of 6

70 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Agilent High Power Optical Attenuator Performance Test

81578A Agilent High Power Optical Attenuator Report No. Date

Insertion Loss Test

Wavelength 850 nm 1310 nm

Measurement Upper test limit 1.5 dB 1.5 dB

Attenuation Accuracy Test

Wavelength 850 nm 1310 nm

Setting/dB Reading/dB Deviation/dB Reading/dB Deviation/dB

1 2 3 4 5 6 7 8

9 10 11 12 13 14 15 25 35 45 55 60

Most Positive Deviation

Upper test limit

Most Negative Deviation

Lower test limit

+0.2dB

-0.2dB

Page 3of 4

+0.2 dB

-0.2 dB

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 71

Performance Tests Performance Test Procedure

Test Record

Agilent High Power Optical Attenuator Performance Test Page 1 of 4

Test Facility:

Report No.:

Date:

Customer:

Tes te d By :

Model: Agilent High Power Optical Attenuator Product Number: #

Serial No. Ambient temperature

Firmware Rev. Relative humidity %

Line frequency Hz

Special Notes:

°C

72 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Performance Test Procedure Performance Tests

Agilent High Power Optical Attenuator Performance Test

Agilent High Power Optical Attenuator Report No. Date:

Test Equipment

# Description Model No. Trace No. Cal. due date

1Mainframe / /

2Power Meter / /

3Laser Source / /

4 Return Loss Module / /

5 Connector Interface / /

6 Single Mode Fiber / /

7 / /

8 / /

Page 2 of 4

9 / /

10 / /

11 / /

12 / /

13 / /

14 / /

15 / /

16 / /

17 / /

18 / /

19 / /

20 / /

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 73

Performance Tests Performance Test Procedure

Agilent High Power Optical Attenuator Performance Test Page 4of 4

81578A

Agilent Modular Optical Attenuator Report No. Date

Attenuation Repeatability Test

Wavelength 850 nm 1310 nm

Setting / dB Deviation / dB Deviation / dB

7 15 24 32 40 48 54 60

Maximum peak-to-peak Deviation

Upper test limit 0.03 dBpp

0.03 dBpp

74 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Cleaning Information

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 77

Cleaning Information

The following Cleaning Information contains some general safety precautions, which must be observed during all phases of cleaning. Consult your specific optical device manuals or guides for full information on safety matters.

Please try, whenever possible, to use physically contacting connectors, and dry connections. Clean the connectors, interfaces, and bushings carefully after use.

If you are unsure of the correct cleaning procedure for your optical device, we recommend that you first try cleaning a dummy or test device.

Agilent Technologies assume no liability for the customer’s failure to comply with these requirements.

78 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Safety Precautions Cleaning Information

Safety Precautions

Please follow the following safety rules:

• Do not remove instrument covers when operating.

• Ensure that the instrument is switched off throughout the cleaning procedures.

• Use of controls or adjustments or performance of procedures other than those specified

may result in hazardous radiation exposure.

• Make sure that you disable all sources when you are cleaning any optical interfaces.

• Under no circumstances look into the end of an optical device attached to optical

outputs when the device is operational. The laser radiation is not visible to the human eye, but it can seriously damage your eyesight.

• To prevent electrical shock, disconnect the instrument from the mains before cleaning. Use a dry cloth, or one slightly dampened with water, to clean the external case parts. Do not attempt to clean internally.

• Do not install parts or perform any unauthorized modification to optical devices.

• Refer servicing only to qualified and authorized personnel.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 79

Cleaning Information Why is it important to clean optical devices?

Why is it important to clean optical devices?

CAU T ION Optical power levels above 100 mW applied to single mode connectors can easily damage

the connector if it is not perfectly clean. Also, scratched or poorly cleaned connectors can destroy optical connectors mechanically. Always make sure that your optical connectors are properly cleaned and unscratched before connection. However, Agilent Technologies Deutschland GmbH assumes no responsibility in case of an operation that is not compliace with the safety instructions as stated above.

In transmission links optical fiber cores are about 9 mm (0.00035") in diameter. Dust and other particles, however, can range from tenths to hundredths of microns in diameter. Their comparative size means that they can cover a part of the end of a fiber core, and thus degrade the transmission quality. This will reduce the performance of your system.

Furthermore, the power density may burn dust into the fiber and cause additional damage (for example, 0 dBm optical power in a single mode fiber causes a power density of approximately 16 million W/m non-repeatable.

Cleaning is, therefore, an essential yet difficult task. Unfortunately, when comparing most published cleaning recommendations, you will discover that they contain several inconsistencies. In this chapter, we want to suggest ways to help you clean your various optical devices, and thus significantly improve the accuracy and repeatability of your lightwave measurements.

). If this happens, measurements become inaccurate and

What materials do I need for proper cleaning?

Some Standard Cleaning Equipment is necessary for cleaning your instrument. For certain cleaning procedures, you may also require certain Additional Cleaning Equipment.

Standard Cleaning Equipment

Before you can start your cleaning procedure you need the following standard equipment:

• Dust and shutter caps

80 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

What materials do I need for proper cleaning? Cleaning Information

• Isopropyl alcohol

• Cotton swabs

• Soft tissues

• Pipe cleaner

• Compressed air

Dust and shutter caps

All of Agilent Technologies’ lightwave instruments are delivered with either laser shutter caps or dust caps on the lightwave adapter. Any cables come with covers to protect the cable ends from damage or contamination.

We suggest these protective coverings should be kept on the equipment at all times, except when your optical device is in use. Be careful when replacing dust caps after use. Do not press the bottom of the cap onto the fiber too hard, as any dust in the cap can scratch or pollute your fiber surface.

If you need further dust caps, please contact your nearest Agilent Technologies sales office.

Isopropyl alcohol

This solvent is usually available from any local pharmaceutical supplier or chemist's shop. Results will vary depending on the purity of the alcohol.

If you use isopropyl alcohol to clean your optical device, do not immediately dry the surface with compressed air (except when you are cleaning very sensitive optical devices). This is because the dust and the dirt is dissolved in the alcohol and will leave behind filmy deposits after the alcohol has evaporated. You should therefore first remove the alcohol and the dust with a soft tissue, and then use compressed air to blow away any remaining filaments.

If possible avoid using denatured alcohol containing additives. Instead, apply alcohol used for medical purposes.

Never drink this alcohol, as it may seriously damage to your health.

Do not use any other solvents, as some may damage plastic materials and claddings. Acetone, for example, will dissolve the epoxy used with fiber optic connectors. To avoid damage, only use isopropyl alcohol.

Cotton swabs

We recommend that you use swabs such as Q-tips or other cotton swabs normally available from local distributors of medical and hygiene products (for example, a supermarket or a chemist's shop). You may be able to obtain various sizes of swab. If this is the case, select the smallest size for your smallest devices.

Ensure that you use natural cotton swabs. Foam swabs will often leave behind filmy deposits after cleaning.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 81

Cleaning Information What materials do I need for proper cleaning?

Use care when cleaning, and avoid pressing too hard onto your optical device with the swab. Too much pressure may scratch the surface, and could cause your device to become misaligned. It is advisable to rub gently over the surface using only a small circular movement.

Swabs should be used straight out of the packet, and never used twice. This is because dust and dirt in the atmosphere, or from a first cleaning, may collect on your swab and scratch the surface of your optical device.

Soft tissues

These are available from most stores and distributors of medical and hygiene products such as supermarkets or chemists' shops.

We recommend that you do not use normal cotton tissues, but multi-layered soft tissues made from non-recycled cellulose. Cellulose tissues are very absorbent and softer. Consequently, they will not scratch the surface of your device over time.

Use care when cleaning, and avoid pressing on your optical device with the tissue. Pressing too hard may lead to scratches on the surface or misalignment of your device. Just rub gently over the surface using a small circular movement.

Use only clean, fresh soft tissues and never apply them twice. Any dust and dirt from the air which collects on your tissue, or which has gathered after initial cleaning, may scratch and pollute your optical device.

Pipe cleaner

Pipe cleaners can be purchased from tobacconists, and come in various shapes and sizes.The most suitable one to select for cleaning purposes has soft bristles, which will not produces scratches.

The best way to use a pipe cleaner is to push it in and out of the device opening (for example, when cleaning an interface). While you are cleaning, you should slowly rotate the pipe cleaner.

Only use pipe cleaners on connector interfaces or on feed through adapters. Do not use them on optical head adapters, as the center of a pipe cleaner is hard metal and can damage the bottom of the adapter.

Your pipe cleaner should be new when you use it. If it has collected any dust or dirt, this can scratch or contaminate your device.

The tip and center of the pipe cleaner are made of metal. Avoid accidentally pressing these metal parts against the inside of the device, as this can cause scratches.

Compressed air

Compressed air can be purchased from any laboratory supplier.

82 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

What materials do I need for proper cleaning? Cleaning Information

It is essential that your compressed air is free of dust, water and oil. Only use clean, dry air. If not, this can lead to filmy deposits or scratches on the surface of your connector. This will reduce the performance of your transmission system.

When spraying compressed air, hold the can upright. If the can is held at a slant, propellant could escape and dirty your optical device. First spray into the air, as the initial stream of compressed air could contain some condensation or propellant. Such condensation leaves behind a filmy deposit.

Please be friendly to your environment and use a CFC-free aerosol.

Additional Cleaning Equipment

Some Cleaning Procedures need the following equipment, which is not required to clean each instrument:

• Microscope with a magnification range about 50X up to 300X

• Ultrasonic bath

• Warm water and liquid soap

• Premoistened cleaning wipes

• Polymer film

• Infrared Sensor Card

Microscope with a magnification range about 50X up to 300X

A microscope can be found in most photography stores, or can be obtained through or specialist mail order companies. Special fiber-scopes are available from suppliers of splicing equipment.

Ideally, the light source on your microscope should be very flexible. This will allow you to examine your device closely and from different angles.

A microscope helps you to estimate the type and degree of dirt on your device. You can use a microscope to choose an appropriate cleaning method, and then to examine the results. You can also use your microscope to judge whether your optical device (such as a connector) is severely scratched and is, therefore, causing inaccurate measurements.

Ultrasonic bath

Ultrasonic baths are also available from photography or laboratory suppliers or specialist mail order companies.

An ultrasonic bath will gently remove fat and other stubborn dirt from your optical devices. This helps increase the life span of the optical devices.

Only use isopropyl alcohol in your ultrasonic bath, as other solvents may cause damage.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 83

Cleaning Information What materials do I need for proper cleaning?

Warm water and liquid soap

Only use water if you are sure that there is no other way of cleaning your optical device without causing corrosion or damage. Do not use hot water, as this may cause mechanical stress, which can damage your optical device.

Ensure that your liquid soap has no abrasive properties or perfume in it. You should also avoid normal washing up liquid, as it can cover your device in an iridescent film after it has been air dried.

Some lenses and mirrors also have a special coating, which may be sensitive to mechanical stress, or to fat and liquids. For this reason we recommend you do not touch them.

If you are not sure how sensitive your device is to cleaning, please contact the manufacturer or your sales distributor.

Premoistened cleaning wipes

Use pre-moistened cleaning wipes as described in each individual cleaning procedure. Cleaning wipes may be used in every instance where a moistened soft tissue or cotton swab is applied.

Polymer film

Polymer film is available from laboratory suppliers or specialist mail order companies.

Using polymer film is a gentle method of cleaning extremely sensitive devices, such as reference reflectors and mirrors.

Infrared Sensor Card

Infrared sensor cards are available from laboratory suppliers or specialist mail order companies.

With the help of this card you are able to inspect the shape of laser light emitted. The invisible laser beam is projected onto the sensor card. The light beam’s infrared wavelengths are refleted at visible wavelengths, so becoming visible to the normal eye as a round spot.

Take care never to look into the end of a fiber or any other optical component, when they are in use. This is because the laser can seriously damage your eyes.

84 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Preserving Connectors Cleaning Information

Preserving Connectors

Listed below are some hints on how best to keep your connectors in the best possible condition.

Making Connections Before you make any connection you must ensure that all cables and connectors are clean.

If they are dirty, use the appropriate cleaning procedure.

When inserting the ferrule of a patchcord into a connector or an adapter, make sure that the fiber end does not touch the outside of the mating connector or adapter. Otherwise you will rub the fiber end against an unsuitable surface, producing scratches and dirt deposits on the surface of your fiber.

Dust Caps and Shutter Caps Be careful when replacing dust caps after use. Do not press the bottom of the cap onto the

fiber as any dust in the cap can scratch or dirty your fiber surface.

When you have finished cleaning, put the dust cap back on, or close the shutter cap if the equipment is not going to be used immediately.

Immersion Oil and Other Index Matching

Compounds

Always keep the caps on the equipment when it is not in use.

All of Agilent Technologies’ lightwave instruments and accessories are shipped with either laser shutter caps or dust caps. If you need additional or replacement dust caps, contact your nearest Agilent Technologies Sales/Service Office.

Wherever possible, do not use immersion oil or other index matching compounds with your device. They are liable to impair and dirty the surface of the device. In addition, the characteristics of your device can be changed and your measurement results affected.

Cleaning Instrument Housings

Use a dry and very soft cotton tissue to clean the instrument housing and the keypad. Do not open the instruments as there is a danger of electric shock, or electrostatic discharge. Opening the instrument can cause damage to sensitive components, and in addition your warranty will be invalidated.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 85

Cleaning Information General Cleaning Procedure

General Cleaning Procedure

Light dirt If you just want to clean away light dirt, observe the following procedure for all devices:

• Use compressed air to blow away large particles.

• Clean the device with a dry cotton swab.

• Use compressed air to blow away any remaining filament left by the swab.

Heavy dirt If the above procedure is not enough to clean your instrument, follow one of the procedures

below.

If you are unsure of how sensitive your device is to cleaning, please contact the manufacturer or your sales distributor

How to clean connectors

Cleaning connectors is difficult as the core diameter of a single mode fiber is only about 9 mm. This generally means you cannot see streaks or scratches on its surface. To be certain of the condition of the surface of your connector and to check it after cleaning, you need a microscope.

In the case of scratches, or of dust that has been burnt onto the surface of the connector, you may have no option but to polish the connector. This depends on the degree of dirtiness, or the depth of the scratches. This is a difficult procedure and should only be performed by a skilled person, and as a last resort as it wears out your connector.

WARN ING Never look into the end of an optical cable that is connected to an active source.

To assess the projection of the emitted light beam you can use an infrared sensor card. Hold the card approximately 5 cm from the output of the connector. The invisible emitted light is projected onto the card and becomes visible as a small circular spot.

Cleaning procedure for high-power

single mode connections

Optical single mode connectors for high-power applications (optical power levels bove 100 mW) require careful cleaning to prevent the power density of burning dust or dirt into the fiber causing permanent damage to the devices and/or connectors. If this happens, measurements become inaccurate and unrepeatable.

The “Preferred Procedure” on page 87 or the “Procedure for Stubborn Dirt” on page 87 must be strictly followed for each part of the optical connection (connector, connector interface, and physical connector interface).

Always make sure that the fiber end-faces are properly cleaned and unscratched before connection. The fiber end faces must be visually inspected using a microscope with a magnification of at leasst 400x. For recommended fiber inspection microscopes, please refer to personnel in Agilent’s Service Team.

86 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

General Cleaning Procedure Cleaning Information

The connection should be made immediately after cleaning and inspection to prevent the connection (connector, connector interface, and physical connector interface) from becoming dusty or dirty again.(

Preferred Procedure An Optical Connector Cleaner, which ressembles a VCR cleaning tape, is a device that can

be used to clean grease from the surface of a connector.

1 Blow away any surface dust with compressed air..

2 Press the button on the sideof the Optical Connector Cleaner device to ensure that a

fresh strip of tape is ready.

3 Position the connector interface on the tape.

4 Holding the connector interface against the tape, rotate the interface about 180

degrees, then slide it across the surface of the tape.

Alternative Procedure Use the following procedure if an Optical Connector Cleaner is not available.

1 Clean the connector by rubbing a new, dry cotton swab over the surface using a small

circular movement.

2 Blow away any remaining lint with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the connector:

1 Moisten a new cotton swab with isopropyl alcohol.

2 Clean the connector by rubbing the cotton swab over the surface using a small circular

movement.

3 Take a new, dry soft tissue and remove the alcohol, dissolved sediment and dust, by

rubbing gently over the surface using a small circular movement.

4 Blow away any remaining lint with compressed air.

An Alternative Procedure A better, more gentle, but more expensive cleaning procedure is to use an ultrasonic bath

with isopropyl alcohol.

1 Hold the tip of the connector in the bath for at least three minutes.

2 Take a new, dry soft tissue and remove the alcohol, dissolved sediment and dust, by

rubbing gently over the surface using a small circular movement.

3 Blow away any remaining lint with compressed air.

How to clean optical head adapters

CAU T IO N Some adapters have an anti-reflection coating on the back to reduce back reflection. This

coating is extremely sensitive to solvents and mechanical abrasion. Extra care is needed when cleaning these adapters.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 87

Cleaning Information General Cleaning Procedure

When using optical head adapters, periodically inspect the optical head’s front window. Dust and metal particles can be propelled through the adapter’s pinhole while inserting the connector ferrule into the receptacle. These dirt particles collect on the head’s front window, which can lead to incorrect results if not removed.

Preferred Procedure Use the following procedure on most occasions.

1 Clean the adapter by rubbing a new, dry cotton swab over the surface using a small

circular movement.

2 Blow away any remaining lint with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the adapter:

1 Moisten a new cotton swab with isopropyl alcohol.

2 Clean the adapter by rubbing the cotton swab over the surface using a small circular

movement.

3 Take a new, dry soft tissue and remove the alcohol, dissolved sediment and dust, by

rubbing gently over the surface using a small circular movement.

4 Blow away any remaining lint with compressed air.

How to clean connector interfaces

CAUTI ON Be careful when using pipe cleaners, as the core and the bristles of the pipe cleaner are

hard and can damage the interface.

Do not use pipe cleaners on optical head adapters, as the hard core of normal pipe cleaners can damage the bottom of an adapter.

Preferred Procedure Use the following procedure on most occasions.

1 Clean the interface, when no lens is connected, by pushing and pulling a new, dry pipe

cleaner into the opening. Rotate the pipe cleaner slowly as you do this.

2 Blow away any remaining lint with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the interface:

1 Moisten a new pipe cleaner with isopropyl alcohol.

2 Clean the interface by pushing and pulling the pipe cleaner into the opening. Rotate the

pipe cleaner slowly as you do this.

3 Using a new, dry pipe cleaner, and a new, dry cotton swab remove the alcohol, any

dissolved sediment and dust.

4 Blow away any remaining lint with compressed air.

88 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

General Cleaning Procedure Cleaning Information

How to clean bare fiber adapters

Bare fiber adapters are difficult to clean. Protect from dust unless they are in use.

CAUTI O N Never use any kind of solvent when cleaning a bare fiber adapter as solvents can:

• Damage the foam inside some adapters.

• Deposit dissolved dirt in the groove, which can then dirty the surface of an inserted fiber.

Preferred Procedure Use the following procedure on most occasions.

1 Blow away any dust or dirt with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the adapter:

1 Clean the adapter by pushing and pulling a new, dry pipe cleaner into the opening.

Rotate the pipe cleaner slowly as you do this.

CAUTI O N Be careful when using pipe cleaners, as the core and the bristles of the pipe cleaner are

hard and can damage the adapter.

2 Clean the adapter by rubbing a new, dry cotton swab over the surface using a small

circular movement.

3 Blow away any remaining lint with compressed air.

How to clean lenses and instruments with an optical glass plate

Some lenses have special coatings that are sensitive to solvents, grease, liquid and mechanical abrasion. Take extra care when cleaning lenses with these coatings. Some instruments, for example, Agilent’s optical heads have an optical glass plate to protect the sensor.

CAU TI O N Do not attempt to access the internal parts of an Agilent N3988A video microscope for

cleaning or for any other purpose.

Lens assemblies consisting of several lenses are not normally sealed. Therefore, use as little alcohol as possible, as it can get between the lenses and in doing so can change the properties of projection.

If you are cleaning an Agilent 8162*A optical head, periodically inspect the optical head’s front window for dust and other particles. Dust and particles can be propelled through the optical head adapter’s pinhole while inserting a connector ferrule into the receptacle. Particles on the optical head’s front window can significantly impair measurement results.

NOTE Do not dry the lens by rubbing with with cloth or other material, which may scratch the lens

surface.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 89

Cleaning Information General Cleaning Procedure

Preferred Procedure Use the following procedure on most occasions.

1 Clean the lens by rubbing a new, dry cotton swab over the surface using a small circular

movement.

2 Blow away any remaining lint with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the lens:

1 Moisten a new cotton swab with isopropyl alcohol.

2 Clean the lens by rubbing the cotton swab over the surface using a small circular

movement.

3 Using a new, dry cotton swab remove the alcohol, any dissolved sediment and dust.

4 Blow away any remaining lint with compressed air.

How to clean instruments with a fixed connector interface

You should only clean instruments with a fixed connector interface when it is absolutely necessary. This is because it is difficult to remove any used alcohol or filaments from the input of the optical block.

It is important, therefore, to keep dust caps on the equipment at all times, except when your optical device is in use.

If you do discover filaments or particles, the only way to clean a fixed connector interface and the input of the optical block is to use compressed air.

If there are fluids or fat in the connector, please refer the instrument to the skilled personnel of Agilent’s service team.

NOTE Both the surface and the jacket of the attached connector should be completely dry and

clean.

CAUTI ON Only use clean, dry compressed air. Make sure that the air is free of dust, water, and oil. If

the air that you use is not clean and dry, this can lead to filmy deposits or scratches on the surface of your connector interface. This will degrade the performance of your transmission system.

Never try to open the instrument and clean the optical block by yourself, because it is easy to scratch optical components, and cause them to become misaligned.

How to clean instruments with a physical contact interface

Remove any connector interfaces from the optical output of the instrument before you begin the cleaning procedure.

90 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

General Cleaning Procedure Cleaning Information

Cleaning interfaces is difficult as the core diameter of a single mode fiber is only about 9 mm. This generally means you cannot see streaks or scratches on the surface. To be certain of the degree of pollution on the surface of your interface and to check whether it has been removed after cleaning, you need a microscope.

WARNI NG Never look into an optical output, because this can seriously damage your eyesight.

To assess the projection of the emitted light beam you can use an infrared sensor card. Hold the card approximately 5 cm from the interface. The invisible emitted light is projected onto the card and becomes visible as a small circular spot.

Optical single mode connections for high-power applications (optical power levels above 100mW) require careful cleaning to prevent the power density of burning dust or dirt into the fiber causing permanent damage of the devices and/or connectors. If this happens, measurements become inaccurate and non-repeatable.

Preferred Procedure Use the following procedure on most occasions.

1 Clean the interface by rubbing a new, dry cotton swab over the surface using a small

circular movement.

2 Blow away any remaining lint with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the interface:

1 Moisten a new cotton swab with isopropyl alcohol.

2 Clean the interface by rubbing the cotton swab over the surface using a small circular

movement.

3 Take a new, dry soft tissue and remove the alcohol, dissolved sediment and dust, by

rubbing gently over the surface using a small circular movement.

4 Blow away any remaining lint with compressed air.

NOTE This procedures must be strictly followed for each part of the optical connection (connector,

connector interface and physical connector interface).

NOTE The connection should be made immediately after cleaning and inspection to prevent the

connection (connector, connector interface and physical connector interface) from getting dusty or dirty again.

NOTE Always make sure that the fiber end faces are properly cleaned and unscratched before

connection. The fiber end faces must be visually inspected using a microscope with a magnification of at least 400x. For recommended fiber inspection microscopes, please refer to Agilent 's service team personnel.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 91

Cleaning Information General Cleaning Procedure

How to clean instruments with a recessed lens interface

For instruments with a deeply recessed lens interface (for example the Agilent 81633A and 81634A Power Sensors) do NOT follow this procedure. Alcohol and compressed air could damage your lens even further.

Keep your dust and shutter caps on when your instrument is not in use. This should prevent it from getting too dirty.

If you must clean such instruments, please refer the instrument to the skilled personnel of Agilent’s service team.

Preferred Procedure Use the following procedure on most occasions.

1 Blow away any dust or dirt with compressed air.

If this is not sufficient, then

a Clean the interface by rubbing a new, dry cotton swab over the surface using a small

circular movement.

b Blow away any remaining lint with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the interface, and using the preferred

procedure is not sufficient.

Using isopropyl alcohol should be your last choice for recessed lens interfaces because of the difficulty of cleaning out any dirt that is washed to the edge of the interface.

1 Moisten a new cotton swab with isopropyl alcohol.

2 Clean the interface by rubbing the cotton swab over the surface using a small circular

movement.

3 Take a new, dry soft tissue and remove the alcohol, dissolved sediment and dust, by

rubbing gently over the surface using a small circular movement.

4 Blow away any remaining lint with compressed air.

How to clean optical devices which are sensitive to mechanical stress and pressure

Some optical devices, such as the Agilent 81000BR Reference Reflector, which has a gold plated surface, are very sensitive to mechanical stress or pressure. Do not use cotton swabs, soft tissues or other mechanical cleaning tools, as these can scratch or destroy the surface.

Preferred Procedure Use the following procedure on most occasions.

1 Blow away any dust or dirt with compressed air.

92 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

General Cleaning Procedure Cleaning Information

Procedure for Stubborn Dirt To clean devices that are extremely sensitive to mechanical stress or pressure you can also

use an optical clean polymer film. This procedure is time-consuming, but you avoid scratching or destroying the surface.

1 Put the film on the surface and wait at least 30 minutes to make sure that the film has

had enough time to dry.

2 Remove the film and any dirt with special adhesive tapes.

Alternative Procedure For these types of optical devices you can often use an ultrasonic bath with isopropyl

alcohol. Only use the ultrasonic bath if you are sure that it won't cause any damage any part of the device.

1 Put the device into the bath for at least three minutes.

2 Blow away any remaining liquid with compressed air.

If there are any streaks or drying stains on the surface, repeat the cleaning procedure.

How to clean metal filters or attenuator gratings

This kind of device is extremely fragile. A misalignment of the grating leads to inaccurate measurements. Never touch the surface of the metal filter or attenuator grating.

Be very careful when using or cleaning these devices. Do not use cotton swabs or soft tissues, as there is the danger that you cannot remove the lint and that the device will be destroyed by becoming mechanically distorted.

Preferred Procedure Use the following procedure on most occasions.

1 Use compressed air at a distance and with low pressure to remove any dust or lint.

Procedure for Stubborn Dirt Do not use an ultrasonic bath as this can damage your device.

Use this procedure when there is greasy dirt on the device:

1 Put the optical device into a bath of isopropyl alcohol, and wait at least 10 minutes.

2 Remove the fluid using compressed air at some distance and with low pressure. If there

are any streaks or drying stains on the surface, repeat the whole cleaning procedure.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 93

Cleaning Information Additional Cleaning Information

Additional Cleaning Information

The following cleaning procedures may be used with other optical equipment:

• How to clean bare fiber ends

• How to clean large area lenses and mirrors

How to clean bare fiber ends

Bare fiber ends are often used for splices or, together with other optical components, to create a parallel beam.

The end of a fiber can often be scratched. You make a new cleave. To do this:

1 Strip off the cladding.

2 Take a new soft tissue and moisten it with isopropyl alcohol.

3 Carefully clean the bare fiber with this tissue.

4 Make your cleave and immediately insert the fiber into your bare fiber adapter in order

to protect the surface from dirt.

Preferred Procedure There is an easy method for removing dust from bare fiber ends.

1. Touch the bare fiber end with adhesive tape. Any dust will be removed.

How to clean large area lenses and mirrors

Some mirrors, as those from a monochromator, are very soft and sensitive. Therefore, never touch them and do not use cleaning tools such as compressed air or polymer film.

Some lenses have special coatings that are sensitive to solvents, grease, liquid and mechanical abrasion. Take extra care when cleaning lenses with these coatings.

Lens assemblies consisting of several lenses are not normally sealed. Therefore, use as little liquid as possible, as it can get between the lenses and in doing so can change the properties of projection.

Preferred Procedure Use the following procedure on most occasions.

1 Blow away any dust or dirt with compressed air.

Procedure for Stubborn Dirt Use this procedure when there is greasy dirt on the lens:

94 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Additional Cleaning Information Cleaning Information

CAU T IO N Only use water if you are sure that there is no other way of cleaning your optical device

without causing corrosion or damage. Do not use hot water, as this may cause mechanical stress, which can damage your optical device.

Some lenses and mirrors also have a special coating, which may be sensitive to mechanical stress, or to fat and liquids. For this reason we recommend you do not touch them.

If you are not sure how sensitive your device is to cleaning, please contact the manufacturer or your sales distributor.

1 Moisten the lens or the mirror with water.

2 Put a little liquid soap on the surface and gently spread the liquid over the whole area.

3 Wash off the emulsion with water, being careful to remove it all, as any remaining

streaks can impair measurement accuracy.

4 Take a new, dry soft tissue and remove the water, by rubbing gently over the surface

using a small circular movement.

5 Blow away remaining lint with compressed air.

Alternative Procedure A To clean lenses that are extremely sensitive to mechanical stress or pressure you can also

use an optical clean polymer film. This procedure is time-consuming, but you avoid scratching or destroying the surface.

1 Put the film on the surface and wait at least 30 minutes to make sure that the film has

had enough time to dry.

2 Remove the film and any dirt with special adhesive tapes.

Alternative Procedure B If your lens is sensitive to water then:

1 Moisten the lens or the mirror with isopropyl alcohol.

2 Take a new, dry soft tissue and remove the alcohol, dissolved sediment and dust, by

rubbing gently over the surface using a small circular movement.

3 Blow away remaining lint with compressed air.

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 95

Cleaning Information Other Cleaning Hints

Other Cleaning Hints

Selecting the correct cleaning method is an important element in maintaining your equipment and saving you time and money. This chapter highlights the main cleaning methods, but cannot address every individual circumstance.

This section contain some additional hints which we hope will help you further. For further information, please contact your local Agilent Technologies representative.

Making the connection Before you make any connection you must ensure that all lightwave cables and connectors

are clean. If not, then use the appropriate cleaning methods.

When you insert the ferrule of a patchcord into a connector or an adapter, ensure that the fiber end does not touch the outside of the mating connector or adapter. Otherwise, the fiber end will rub up against something which could scratch it and leave deposits.

Lens cleaning papers Some special lens cleaning papers are not suitable for cleaning optical devices like

connectors, interfaces, lenses, mirrors and so on. To be absolutely certain that a cleaning paper is applicable, please ask the salesperson or the manufacturer.

Immersion oil and other index matching

compounds

Cleaning the housing and the mainframe When cleaning either the mainframe or the housing of your instrument, only use a dry and

Do not use immersion oil or other index matching compounds with optical sensors equipped with recessed lenses. They are liable to dirty the detector and impair its performance. They may also alter the property of depiction of your optical device, thus rendering your measurements inaccurate.

very soft cotton tissue on the surfaces and the numeric pad.

Never open the instruments as they can be damaged. Opening the instruments puts you in danger of receiving an electrical shock from your device, and renders your warranty void.

96 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

Index

Attenuator 7

Cleaning 63

Additional equipment 69 Connector Interfaces 74 General Procedure 72 High-power single mode connectors 72 How to clean connectors 72 Importance of 66 Materials required 66 Preserving Connectors 71 Safety Precautions 65

Connectors

How to clean 72 Preserving 71

Conventions 7

Index

Definition of Terms 23

Attenuation 24 Attenuation flatness 24 Attenuation range 25 Attenuation setting mode 25 Attenuation uncertainty 25 Constant operating conditions 25 Insertion Loss 26 Insertion loss flatness 26 Maximum Input Power 26 Operating temperature 27 Operation Temperature 27 Polarization Dependent Loss (PDL) 27 Polarization Extinction Ratio (PER) 27 Polwer setting mode 27 Power setting 27 Relative power meter uncertainty 27 Repeatability 28 Resolution 28 Return Loss 28 Settling Time 29 Shutter Isolation 29 Total Loss 30 Transition speed 30 Wavelength range 30

Firmware

Prerequisites 4 Revision Checking 6

Front Panel

Agilent 81570A 8 Agilent 81571A 8 Agilent 81576A 10

Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition 97

Index

Agilent 81577A 10 Agilent 81578A 9 Controls and Indicators 11

Getting Started 5

Inspection 3

Line Power 4

Mueller method 48

Optical Output 13

Angled & Straight Contact Connectors 13

Optional features 17

Performance Test

Procedure 38 Required Test Equipment 36

Performance Tests 35

Safety

Cleaning 65 Symbols 3 Warnings & Cautions 3, 4

Specifications 31

Variable optical attenuator modules for multimode applications 34 Variable optical attenuator modules for single mode applications 32 Variable optical attenuator modules with power control for single mode applications 33

Storage & Shipment 4

Use Models 11 User’s Guides 18

Wavelength flatness test 43

98 Agilent 81570A, 71A, 76A, 77A & 78A Variable Optical Attenuators, Eigth Edition

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 Agilent Technologies GmbH 2005

Printed in Germany September 2005 Eight edition, September 2005

81570-90A01

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Agilent 81570A User's Guide

Specifications and Main Features

Frequently Asked Questions

User Manual