Keysight N7776C, N7778C, N7779C User Manual

Download

Keysight N777-C Series Tunable Laser Family

N7776C Tunable Laser Source N7778C Tunable Laser Source N7779C Tunable Laser Source

User’s Guide

Notices

CAUTION

WARNING

No part of this manual may be reproduced in any form or by any means (including electronic storage and retrieval or translation into a foreign language) without prior agreement and written consent from Keysight Technologies as governed by United States and international copyright laws.

Manual Part Number

N7770-90B02

Edition

Edition 2.1, February 2021 Keysight Technologies Deutschland GmbH Herrenberger Strasse 130, 71034 Böblingen, Germany

Technology Licenses

The hardware and/or software described in this document are furnished under a license and may be used or copied only in accordance with the terms of such license.

U.S. Government Rights

The Software is “commercial computer software,” as defined by Federal Acquisition Regulation (“FAR”) 2.101. Pursuant to FAR

12.212 and 27.405-3 and Department of Defense FAR Supplement

(“DFARS”) 227.7202, the U.S. government acquires commercial computer software under the same terms by which the software is customarily provided to the public. Accordingly, Keysight provides the Software to U.S. government customers under its standard commercial license, which is embodied in its End User License Agreement (EULA), a copy of which can be found at:

http://www.keysight.com/find/sweula.

The license set forth in the EULA represents the exclusive authority by which the U.S.

government may use, modify, distribute, or disclose the Software. The EULA and the license set forth therein, does not require or permit, among other things, that Keysight: (1) Furnish technical information related to commercial computer software or commercial computer software documentation that is not customarily provided to the public; or (2) Relinquish to, or otherwise provide, the government rights in excess of these rights customarily provided to the public to use, modify, reproduce, release, perform, display, or disclose commercial computer software or commercial computer software documentation. No additional government requirements beyond those set forth in the EULA shall apply, except to the extent that those terms, rights, or licenses are explicitly required from all providers of commercial computer software pursuant to the FAR and the DFARS and are set forth specifically in writing elsewhere in the EULA. Keysight shall be under no obligation to update, revise or otherwise modify the Software. With respect to any technical data as defined by FAR 2.101, pursuant to FAR

12.211 and 27.404.2 and DFARS 227.7102, the U.S. government acquires no greater than Limited Rights as defined in FAR

27.401 or DFAR 227.7103-5 (c), as applicable in any technical data.

Warranty

THE MATERIAL CONTAINED IN THIS DOCUMENT IS PROVIDED "AS IS," AND IS SUBJECT TO BEING CHANGED, WITHOUT NOTICE, IN FUTURE EDITIONS. FURTHER, TO THE MAXIMUM EXTENT PERMITTED BY APPLICABLE LAW, KEYSIGHT DISCLAIMS ALL WARRANTIES, EITHER EXPRESS OR IMPLIED WITH REGARD TO THIS MANUAL AND ANY INFORMATION CONTAINED HEREIN, INCLUDING BUT NOT LIMITED TO THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. KEYSIGHT SHALL

NOT BE LIABLE FOR ERRORS OR FOR INCIDENTAL OR CONSEQUENTIAL DAMAGES IN CONNECTION WITH THE FURNISHING, USE, OR PERFORMANCE OF THIS DOCUMENT OR ANY INFORMATION CONTAINED HEREIN. SHOULD KEYSIGHT AND THE USER HAVE A SEPARATE WRITTEN AGREEMENT WITH WARRANTY TERMS COVERING THE MATERIAL IN THIS DOCUMENT THAT CONFLICT WITH THESE TERMS, THE WARRANTY TERMS IN THE SEPARATE AGREEMENT WILL CONTROL.

Safety Notices

A CAUTION notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly performed or adhered to, could result in damage to the product or loss of important data. Do not proceed beyond a CAUTION notice until the indicated conditions are fully understood and met.

A WARNING notice denotes a hazard. It calls attention to an operating procedure, practice, or the like that, if not correctly performed or adhered to, could result in personal injury or death. Do not proceed beyond a WARNING notice until the indicated conditions are fully understood and met.

2 Keysight N777-C Series Tunable Laser Family User’s Guide

Safety Summary

General This product is a Protection Class 1 instrument (provided with a protective earth terminal)

The following general safety precautions must be observed during all phases of operation of this instrument. Failure to comply with these precautions or with specific warnings or operating instructions in the product manuals violates safety standards of design, manufacture, and intended use of the instrument. Keysight Technologies assumes no liability for the customer's failure to comply with these requirements. Product manuals are provided on the Web. Go to www.keysight.com and type in your product number in the Search field at the top of the page.

and has been manufactured and tested according to international safety standards. The protective features of this product may be impaired if it is used in a manner not specified in the operation instructions.

All Light Emitting Diodes (LEDs) used in this product are Class 1 LEDs as per IEC 60825-1:2014.

Environment Conditions

Tempe rat ure

Before Applying Power

Ground the Instrument

Do Not Operate in an

Explosive Atmosphere

This instrument is intended for indoor use in an Overvoltage Category II, pollution degree 2 environment. It is designed to operate at a maximum relative humidity (RH) of 80%, non-condensing and at altitudes of up to 2000 meters. Refer to the specifications tables for the AC mains voltage requirements and ambient operating temperature range.

The instrument should be protected from temperature extremes and changes in temperature that may cause condensation within it. The operating temperature is from 10 °C to +35 °C The storage temperature is from –40 °C to +70 °C (Option D00, standard front panel)

___________________________ __ –30 °C to +70 °C (Option D01, touchscreen display)

Verify that all safety precautions are taken. The power cable inlet of the instrument serves as a device to disconnect from the mains in case of hazard. The instrument must be positioned so that the operator can easily access the power cable inlet. When the instrument is rack mounted the rack must be provided with an easily accessible mains switch.

To minimize shock hazard, the instrument chassis and cover must be connected to an electrical protective earth ground. The instrument must be connected to the AC power mains through a grounded power cable, with the ground wire firmly connected to an electrical ground (safety ground) at the power outlet. Any interruption of the protective (grounding) conductor or disconnection of the protective earth terminal will cause a potential shock hazard that could result in personal injury.

Do not operate the instrument in the presence of flammable gases or fumes.

Do Not Remove the

Instrument Cover

Keysight N777-C Series Tunable Laser Family User’s Guide 3

Operating personnel must not remove instrument covers. Component replacement and internal adjustments must be made only by qualified personnel.

Instruments that appear damaged or defective should be made inoperative and secured against unintended operation until they can be repaired by qualified service personnel.

Instrument Markings

Instrument Marking Description

The instruction manual symbol. The product is marked with this warning symbol when it is necessary for the user to refer to the instructions in the manual.

Standby supply. Unit is not completely disconnected from AC mains when switch is off.

The CE mark is a registered trademark of the European Community.

The CSA mark with the 'c' and 'us' subscript indicates the instrument is certified to the applicable Canadian and United States of America standards respectively.

The RCM mark is a registered trademark of the Australian Communications and Media

Authority

This symbol is a South Korean Class A EMC Declaration, with the product identification code "R-R-Kst-3E18526". R - Identification of authorization prefix. R - Identification of basic certification information. Kst - Identification of applicant's information 3E18526 - Product identification. This is a Class A instrument suitable for professional use and in electromagnetic environment outside of the home.

The recycling symbol indicates the general ease with which the instrument can be recycled.

China Restricted Substance Product Label. The EPUP (environmental protection use period) number in the center indicates the time period during which no hazardous or toxic substances or elements are expected to leak or deteriorate during normal use and generally reflects the expected useful life of the product.

4 Keysight N777-C Series Tunable Laser Family User’s Guide

South Korean Class A EMC Declaration

ۉࡅ࢒߄έה

ࢇЕ߶הࡈ୚ˁ߾۰یࡈଟּࢶࡳԻࢶଢ۽ૡɼձ؇ࡵԻ۰ɼࢽࡈ୚ˁ߾۰ی ࡈଜЕˁࡉࢷળɾۺࢂࡉԮɼ࢑ݡТЬ

یࡈ࢕ ߇ΰחࡵ߶הࡈ ؏ܞݦ࢕ࢢ߾փ ࢶࡈଞЬ

Information to the user:

This instrument has been conformity assessed for used in business environments. In a residential environment this equipment may caused radio interference.

This EMC statement applies to the equipment only for use in business environment.

Compliance and Environmental Information

Table 1 Compliance and Environmental Information

Safety Symbol Description

This product complies with 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 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 Keysight office, or see

http://about.keysight.com/en/companyinfo/environment/takeback.shtml for more

information.

Declaration of Conformity

Declarations of Conformity for this product and for the Keysight products may be downloaded from the Web. Go to http://www.keysight.com/go/conformity.

You can then search by product number to find the latest Declaration of Conformity.

Keysight N777-C Series Tunable Laser Family User’s Guide 5

1 General Operating Considerations

Safety Summary 3

Instrument Markings 4

South Korean Class A EMC Declaration 5

Compliance and Environmental Information 5

Declaration of Conformity 5

Overview 14

Laser Safety Information 15

Initial Safety Information for Keysight N777-C Family Lasers 15 Laser Safety Labels 16 Laser Safety Symbols 17

Operating Environment 18

Handling the Instrument 20

Storage and Shipment 20 Carrying the Instrument 20 Rack Mount the Instrument 20

Obtaining Source Code 22

2 Getting Started

Initial Inspection 24

Initial Inspection 24 Claims and Repackaging 24 Return Shipments to Keysight Technologies 24 Deleting User Data 25

Keysight N777-C Series Tunable Laser Family User’s Guide 7

Contents

Power Supply Requirements 26

Line Power Requirements 26

N777-C Series of Tunable Laser Family 28

The Keysight N7776C Top-Line Tunable Laser Source 28 The Keysight N7778C Value Line Tunable Laser Sources 28 The Keysight N7779C Basic Line Step-Tunable Laser Source 29 O-band option for Silicon Photonics/ Integrated Photonics

Applications E-band option for CWDM8 Component Testing 29

N777-C Front and Rear Panel 30

Input/Output Signals 31 Optical Output 32

LAN Interface 34

The LAN LED 34 The LAN Reset button 34 USB Interface 35

Powering Up the Instrument 36

Connecting the Instrument 37

Connecting over USB 37 Connecting over LAN 38

N777-C User Interface 41

3 Definition of Terms

Definition of Terms 44

General Definitions 44 Absolute wavelength accuracy (continuous sweep mode) 45 Absolute wavelength accuracy (stepped mode) 45 Dynamic power reproducibility (continuous sweep mode) 45 Dynamic relative power flatness (continuous sweep mode) 46 Effective linewidth 46

8 Keysight N777-C Series Tunable Laser Family User’s Guide

Linewidth 47 Maximum output power 47 Mode-hop free tunability 48 Operating temperature and humidity 48 Output isolation 48 Polarization extinction ratio 48 Power flatness versus wavelength 49 Power linearity 50 Power repeatability 50 Power stability 51 Relative intensity noise (RIN) 51 Relative wavelength accuracy (continuous sweep mode) 52 Relative wavelength accuracy (stepped mode) 52 Return loss 53 Side-mode suppression ratio 53 Signal to source spontaneous emission (SSE) ratio 54 Signal to total source spontaneous emission ratio 55 Wavelength range 55 Wavelength repeatability (continuous sweep mode) 55 Wavelength repeatability (stepped mode) 56 Wavelength resolution 57 Wavelength stability 57

Contents

4 N777-C Web Interface Reference

N777-C Web Interface 60

Controlling N777-C Instruments 62

Control Instrument Tab 62 How to set Wavelength? 65 How to Set Power? 65 How to Perform a Wavelength Sweep? 66 How to Use Triggers? 70 How to set Modulation? 71 How to Lock/Unlock the Instrument? 72 How to Turn ON/OFF the Laser? 73

Keysight N777-C Series Tunable Laser Family User’s Guide 9

Contents

How to Use Auxiliary Functions 74

How to Get Current Instrument Settings? 74 How to Identity a Particular instrument? 75 How to Capture an Image of the Graph? 75 How to Save/Recall the Web Interface Settings? 75 Logging In/Out of the N777-C Web Interface 76 How to Create/Change the Password? 77 What If You Forget Your Password? 77 How to perform Realignment? 77 Lambda Zeroing 78 Update Rate 79 Reboot Device 80 How to Configure LAN? 80

5 N777-C Instrument’s Front Panel Display

N777-C Instrument’s Front Panel Display 86

Controlling N777-C Instruments 88

Control Instrument Window 88 How to set Wavelength? 91 How to Set Power? 92 How to Perform a Wavelength Sweep? 93 How to Use Triggers? 97 How to set Modulation? 100 How to Lock/Unlock the Instrument? 101 How to Turn ON/OFF the Laser Output? 101 How to Get Current Instrument Settings? 101 How to Configure LAN? 103

10 Keysight N777-C Series Tunable Laser Family User’s Guide

6 Maintenance

Contents

Cleaning Instructions 108

Safety Precautions 108 Why is it important to clean optical devices? 108 What materials do I need for proper cleaning? 109 General Cleaning Procedure 111

Further Cleaning Information 112

Firmware Upgrades 113

Requirements 113

Contact Keysight Technologies 114

Keysight N777-C Series Tunable Laser Family User’s Guide 11

Keysight N777-C Series Tunable Laser Family

User’s Guide

1 General Operating

Considerations

Overview / 14 Laser Safety Information / 15 Operating Environment / 18 Handling the Instrument / 20 Obtaining Source Code / 22

1 General Operating Considerations

WARNING

Overview

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. Keysight Technologies assumes no liability for the customer’s failure to comply with these requirements.

Ensure the proper usage for the instrument. The protection provided by the instrument may be impaired. The operator of this instrument is advised to use the equipment in a manner as specified in this document

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

Some circuits are powered whenever the instrument is connected to the AC power source. To disconnect from the line power, disconnect the power cord either at the rear power inlet or at the AC line power source (receptacle). One of these must always be accessible. If the instrument is in a cabinet, it must be disconnected from the line power by the system’s line power switch.

14 Keysight N777-C Series Tunable Laser Family User’s Guide

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.).

Please pay attention to the following laser safety warning: Under no circumstances look into the end of an optical cable attached to

Laser Safety Information

Initial Safety Information for Keysight N777-C Family Lasers

General Operating Considerations 1

The laser sources specified by this user’s guide are classified according to IEC 60825-1:2014.

The laser sources comply with 21 CFR 1040.10 except for deviations pursuant to Laser Notice No. 50 dated 2007, June 24.

Table 2 Laser Source Specification

N7776C #216 N7778C #216 N7779C #216

Laser type EC-Laser

Wavelength range 1450 – 1650 nm 1440 – 1640 nm 1490 – 1640 nm 1340 – 1495 nm 1240 – 1380 nm

Max. CW output power

Beam waist diameter 9 µm 9 µm 9 µm 9 µm 9 µm

Numerical aperture 0.1 0.1 0.1 0.1 0.1

Laser class according to IEC 60825-1:2014

Max. permissible CW output power

* Max. CW output power is defined as the highest possible optical power that the laser source can produce at its output connector.

InGaAsP

< 25 mW < 25 mW < 25 mW < 60 mW < 30 mW

1M 1M 1M 1M 1M

163 mW 163 mW 163 mW 163 – 500 mW 55 – 500 mW

N7778C #215 N7776C #116

EC-Laser InGaAsP

N7778C #116 N7779C #116

EC-Laser InGaAsP

N7776C #114 N7778C #114 N7779C #114

EC-Laser InGaAsP

N7776C #113 N7778C #113 N7779C #113

EC-Laser InGaAsP

Keysight N777-C Series Tunable Laser Family User’s Guide 15

1 General Operating Considerations

WARNING

Laser Safety Labels

Laser Class 1M Label

Figure 1 Laser Class 1M Label

A sheet of laser safety labels is included with the laser instrument. In order to meet the requirements of IEC 60825-1:2014, we recommend that you stick the laser safety labels, in your language, onto a suitable location on the outside of the instrument where they are clearly visible to anyone using the instrument.

Please pay attention to the following laser safety warning: Under no circumstances look into the end of an optical cable attached to

the optical output when the instrument is operational. The laser radiation can seriously damage your eyesight. Do not enable the laser when there is no fiber attached to the optical output connector. The laser can be enabled by pressing the “active” button close to the optical output connector on the front panel of the instrument or by remote control. The laser is on when the green LED, above the optical output, on the front panel of the instrument is lit. The use of optical instruments with this product will increase eye hazard. The laser instrument has a built-in safety circuitry which will disable the optical output in the case of a fault condition. Refer servicing only to qualified and authorized personnel.

16 Keysight N777-C Series Tunable Laser Family User’s Guide

Laser 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.

Invisible laser radiation.

General Operating Considerations 1

Keysight N777-C Series Tunable Laser Family User’s Guide 17

1 General Operating Considerations

WARNING

Operating Environment

Overview

In order for the instrument to meet specifications, the operating environment must be within these limits. Refer to Safety Summary on page 3.

The instrument is not designed for outdoor use. To prevent potential fire or shock hazard, do not expose the instrument to rain or other excessive moisture.

Instrument Cooling

The instrument has a cooling fan mounted internally.

Mount or position your instrument upright and horizontally, as shown in the following figure so that air can circulate through it freely.

18 Keysight N777-C Series Tunable Laser Family User’s Guide

Operating Position

When operating the instrument choose a location that provides at least 75 mm (3 inches) of clearance at the rear, and at least 25 mm (1 inch) of clearance at each side. Failure to provide adequate air clearance may result in excessive internal temperature, reducing instrument reliability. The instrument should not be operated when resting on its rear or side panels.

Figure 2 shows the correct operating position of Keysight N777-C

instrument.

General Operating Considerations 1

25 mm (1 inch)

25 mm

(1 inch)

75 mm (3 inches)

Figure 2 Operating Position of the Instrument

Keysight N777-C Series Tunable Laser Family User’s Guide 19

1 General Operating Considerations

Strap

NOTE

Handling the Instrument

Storage and Shipment

Carrying the Instrument

Lasers can be stored or shipped at temperatures between –40 °C to +70 °C (Option D00, standard front panel) and between –30 °C to +70 °C (Option D01, touchscreen display). Protect the laser from temperature extremes that may cause condensation within it.

The Keysight N777-C Tunable Laser System can be stored either in its operating position or on its back legs. The back legs protect the connectors on the back panel from damage.

Grasp the strap to carry the instrument.

Figure 3 Carrying an Instrument

Rack Mount the Instrument

You can mount the instrument in a standard 19-inch rack cabinet using an optional kit, which includes instructions and mounting hardware.

Remove the carrying strap, and the front and rear rubber bumpers feet, before mounting the instrument in a rack.

20 Keysight N777-C Series Tunable Laser Family User’s Guide

General Operating Considerations 1

To rack mount a single instrument, order adapter kit N7799C-2CM.

Figure 4 shows an example where an instrument is mounted on a rack:

Figure 4 Instrument Mounted on a Rack

Keysight N777-C Series Tunable Laser Family User’s Guide 21

1 General Operating Considerations

Obtaining Source Code

This product uses open source packages. To the extent required by the applicable open source license(s), Keysight makes source code available upon request. To request source code, please contact Keysight Support at

www.keysight.com/main/support.jspx.

Third party software acknowledgments and licenses for the N777-C series with the embedded Linux operating system are located at:

www.keysight.com/find/N7776C

22 Keysight N777-C Series Tunable Laser Family User’s Guide

Keysight N777-C Series Tunable Laser Family

User’s Guide

2 Getting Started

Initial Inspection / 24 Power Supply Requirements / 26 N777-C Series of Tunable Laser Family / 28 N777-C Front and Rear Panel / 30 LAN Interface / 34 Powering Up the Instrument / 36 Connecting the Instrument / 37 N777-C User Interface / 41

2 Getting Started

WARNING

Initial Inspection

Claims and Repackaging

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 Keysight Technologies Sales/Service Office.

You MUST return malfunctioning instruments to a Keysight Technologies Sales/Service Center for repair and calibration.

If physical damage is evident or if the instrument does not meet specification when received, notify the carrier and the nearest Keysight Technologies Sales/Service Office. The Keysight Technologies Sales/ Service Office will arrange for repair or replacement of the unit without waiting for settlement of the claim against the carrier.

Return Shipments to Keysight Technologies

If the instrument is to be shipped to an Keysight Technologies Sales/ Service Office, attach a tag showing owner, return address, model number and full serial number and the type of service required.

The original shipping carton and packing material may be reusable, but the Keysight Technologies Sales/Service Office will provide information and recommendations on materials to be used if the original packing is no longer available or reusable. General instructions for repackaging are as follows:

• Wrap instrument in heavy paper or plastic.

• Use strong shipping container. A double wall carton made of 350-pound test material is adequate.

24 Keysight N777-C Series Tunable Laser Family User’s Guide

• Use enough shock absorbing material (3 to 4 inch / 7.5 to 10 cm layer)

• Seal shipping container securely.

• Mark shipping container FRAGILE to encourage careful handling.

• In any correspondence with Keysight, refer to the instrument by model

Deleting User Data

If you need to delete all your logged data and user configurations, press and hold the LAN Reset button (approx. 5 seconds) to reset the instrument and all your logged data and user configurations will be deleted.

Getting Started 2

around all sides of the instrument to provide a firm cushion and prevent movement inside container. Protect control panel with cardboard.

number and serial number.

Keysight N777-C Series Tunable Laser Family User’s Guide 25

2 Getting Started

CAUTION

Power Supply Requirements

Line Power Requirements

Line Power Cable

The instrument complies with Overvoltage Category II and can operate from the single-phase AC power source that supplies between 100 V and 240 V at a frequency in the range 50/60 Hz. The maximum voltage fluctuation is 10% of the nominal supply voltage. The maximum power consumption is 200 VA with all options installed.

In accordance with international safety standards, the instrument has a three-wire power cable. When connected to an appropriate AC power receptacle, this cable earths the instrument cabinet.

Please note that the switch on the front panel of the instrument does not stop the flow of power to the instrument.

If you need to turn off the power, unplug the instrument at the mains or remove the power cable connector from the appliance coupler at the rear of the instrument. For this reason, the power cable connection should be easily accessible - allowing you to turn off the power quickly. If the instrument is in a cabinet, it must be disconnected from the line power by the system’s line power switch.

26 Keysight N777-C Series Tunable Laser Family User’s Guide

The power switch allows you to switch between stand-by mode and power-on mode.

Figure 5 Power LED on the Front Panel of the Instrument

Getting Started 2

When the instrument is in stand-by mode, the Power LED is orange. When the instrument is powered-on, the Power LED is green.

The AC power requirements are summarized on the rear panel of the instrument.

Figure 6 AC Power Requirement Markings

Keysight N777-C Series Tunable Laser Family User’s Guide 27

2 Getting Started

N777-C Series of Tunable Laser Family

The Keysight Technologies N777-C Family of Tunable Laser Sources offers the full wavelength range from 1240 nm to 1650 nm with no wavelength gaps.

The N777-C tunable laser sources realize the cost efficiency and performance required to test components for coarse and dense wavelength division multiplexing (CWDM, DWDM, 100GBASE-LR4) and passive optical networks (PON). Whether you need to verify the design of demanding optical components or adjust more wavelength-selective switches per hour, or you simply need a stable, tunable optical source, the N777-C family of tunable lasers offers a suitable model.

All N777-C models are based on a common cavity and laser instrument design and share a narrow linewidth, excellent long-term stability and low spontaneous emission level. They are software compatible with the 8160xA and 81600B lasers, the industry standards for more than a decade, but occupy 1 height unit less rack space.

For further details on its features, application and specifications, refer to the product datasheet available on www.keysight.com.

28 Keysight N777-C Series Tunable Laser Family User’s Guide

The Keysight N7776C Top-Line Tunable Laser Source

The new Keysight N7776C top line tunable laser source is designed to reach best-in-class accuracy and sub-picometer repeatability in static and swept operation for outstanding test efficiency.

With the product family’s lowest spontaneous emission level, the N7776C enables the validation of extremely deep filters. It also offers the best wavelength accuracy in the family – enabled by its high-resolution wavelength reference unit that provides real-time tracking and control and includes a gas cell for excellent long-term stability and self-adjustment capability.

The Keysight N7778C Value Line Tunable Laser Sources

The new N7778C value line tunable laser source offers a peak output power of more than +12 dBm, at least 75 dB/nm above its spontaneous emission level. It features a typical wavelength repeatability of ±1.5 pm at two-way sweeps up to 200 nm/s. The N7778C’s balance of features, performance and price makes it suitable for cost-effective, high-throughput manufacturing-floor component testing as well as for coherent transmission experiments.

The Keysight N7779C Basic Line Step-Tunable Laser Source

The new N7779C basic line tunable laser source, like the other new N777-C models, can step quickly to discrete wavelengths with a resolution of 0.1 pm and a typical wavelength repeatability of ±3 pm, making it ideal for cost-effective testing of broadband optical devices. With wavelength setting times like 300 ms, rapid stepped sweeps are possible. Like the other lasers in the N777-C family, it delivers more than +12 dBm peak output power with low spontaneous emission levels. At ±0.01 dB power stability over an hour, it can also serve as a static local oscillator with a wide tuning range for receiver testing or transmission experiments.

O-band option for Silicon Photonics/ Integrated Photonics Applications

The N777-C option 113 covers the wavelength range from 1240 nm to 1380 nm for an important set of applications. Equipped with PMF output fiber, these are a good match for testing and developing components with Silicon Photonics technology. Verifying the spectral responsivity and the sensitivity of receiver optical subassemblies (ROSA) for 100G Ethernet benefit from more than +10 dBm output power - enough to allow for external modulation in BER testing. Combined with very low SSE levels, Option 113 is ideal for testing wavelength filters for LR4 components.

Getting Started 2

E-band option for CWDM8 Component Testing

The N777-C option 114 covers the wavelength range from 1340 nm to 1495 nm. Combined with the other options, this allows measurements over all CWDM channels, such as for CWDM8 devices. Components for Raman amplification also use this wavelength range.

Keysight N777-C Series Tunable Laser Family User’s Guide 29

2 Getting Started

N777-C Front and Rear Panel

This section provides information on the front and rear panels of the N777-C Series Tunable Laser Source.

Figure 7 shows the front panel of the N777-C Series Tunable Laser Source

with the optional display unit (Option D01):

Figure 7 Front Panel of the N777-C Instrument with Display

30 Keysight N777-C Series Tunable Laser Family User’s Guide

Figure 8 shows the front panel of the N777-C Series Tunable Laser Source

without the display (Option D00):

Figure 8 Front Panel of the N777-C Instrument without Display

Figure 9 shows the rear panel of the N777-C Series Tunable Laser Source:

CAUTION

Figure 9 Rear Panel of the N777-C Instrument

Input/Output Signals

Front Panel:

There is one BNC input connector on the front panel of the Keysight N777-C.

Getting Started 2

Keysight N777-C Series Tunable Laser Family User’s Guide 31

An absolute maximum of ±5 V can be applied as an external voltage to the BNC connector.

Rear Panel:

There is one input BNC connector: Trigger In. This is a TTL input.

A maximum of 5 V can be applied as an external voltage to this input connector.

There is one output BNC connector: Trigger Out. This is a TTL output. Do not apply an external voltage to this connector.

Do not connect multiple Trigger Outputs together.

2 Getting Started

Slow Axis (Polarization Axis)

Connector Key

Fiber Cladding

Fiber Core

(9-μm Diameter)

Stress Rods

Not to Scale

Optical Output

Polarization Maintaining Fiber

All Keysight N777-C Series Tunable Laser Family instruments include polarization maintaining fiber (PMF) outputs, aligned to maintain the state of polarization.

The fiber is of Panda type, with TE mode in the slow axis in line with the connector key. A well-defined state of polarization ensures constant measurement conditions.

Figure 10 PMF Output Connector

Angled Contact Connectors

32 Keysight N777-C Series Tunable Laser Family User’s Guide

The N777-C Series Tunable Laser instruments are outfitted with an angled polished connector. Angled contact connectors help you to control return loss. With angled fiber end-faces, reflected light tends to reflect into the cladding, reducing the amount of light that reflects back to the source. When reflected light remains in the fiber core at two or more locations along the optical path, such as at an open straight-polished connector output to a power meter, double reflections result in multi-path interference of the coherent light and thus power instability in the measurements.

Getting Started 2

CAUTION

Straight Contact

Connector Symbol

Angled Contact

Connector Symbol

NOTE

Since the contact connector on your instrument is angled, you can only use cables with angled connectors at the instrument.

Figure 11 Angled and Straight Contact Connector Symbol

Figure 11 shows the symbols that tell you whether the contact connector

of your instrument 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 and connect angled contact fiber end connectors with green sleeves to angled contact connectors.

Keysight N777-C Series Tunable Laser Family User’s Guide 33

You cannot connect angled non-contact fiber end connectors with orange sleeves directly to the instrument.

2 Getting Started

Red LAN

No LAN link

Yellow LAN Green LAN

No IP Addr ess

LAN li nk

LAN Interface

The LAN LED

When the LAN connection is made, you will see the following indicators:

There may be a delay between making the LAN link (yellow status) and getting the IP address (green status). This delay may be longer if there is no DHCP server, for example when the instrument is connected directly to a PC.

The LAN Reset button

This recessed button has two functions.

• Pressing the button briefly invokes a preset of the instrument and restores default measurement settings. This is equivalent to the programming command:

:SYSTem:PRESet

• Pressing and holding the button for 5 seconds will reset the LAN parameters to the factory default. This includes removing the password. This is equivalent to the following sequence of programming command:

:SYSTem:COMMunicate:ETHernet:RESet

34 Keysight N777-C Series Tunable Laser Family User’s Guide

USB Interface

NOTE

USB Type-B Connector

Getting Started 2

It is recommended to use the Keysight IO Libraries Suite to enable instrument communication for a variety of development environments. It is available at: http://keysight.com/find/iolibs

The instrument is a USB device, with a USB Type-B connector which is available on the rear side of the instrument.

Keysight N777-C Series Tunable Laser Family User’s Guide 35

2 Getting Started

Powering Up the Instrument

When you power on the instrument, the LEDs on the front panel show the various stages of the instrument.

Power LAN Status

Yellow Standby mode Searching for LAN Warming Up

Green ON Connected with LAN

Blinking Green Communicating

Red Not connected

over LAN / USB

36 Keysight N777-C Series Tunable Laser Family User’s Guide

Connecting the Instrument

Connecting over USB

Getting Started 2

1 Power on the instrument. 2 Connect the PC to the instrument using a USB cable. 3 The operating system will detect and display the new instrument as a

new drive.

4 Double-click on this new drive. It will show a shortcut to start the user

interface.

5 Double -click on this shortcut. This will open the user interface of the

instrument in a browser.

Keysight N777-C Series Tunable Laser Family User’s Guide 37

2 Getting Started

Connecting over LAN

1 Make sure the instrument is connected to the LAN, and that the LAN

LED on the front panel is green.

2 If it is not already running, start the Keysight Connection Expert

software.

The Discovery Service automatically discovers LAN instruments on the same subnet as the PC on which the service is running.

3 To add LAN instruments to the Connection Expert My Instruments list:

a Click, select LAN Instrument from the context list. This opens the list

of discovered LAN instruments.

b Click the check box for each instrument you want to add to the list. c Click OK.

38 Keysight N777-C Series Tunable Laser Family User’s Guide

Getting Started 2

4 To manually add LAN instruments outside of the local subnet:

a Click, select LAN Instrument from the context list. This opens the list

of discovered LAN instruments.

b Click the Enter Address tab. c Enter the LAN address or host name and select the protocol used to

communicate with the instrument. Supported protocols are VXI-11 and Socket.

d Click OK.

Keysight N777-C Series Tunable Laser Family User’s Guide 39

2 Getting Started

5 Linux or macOS can use the zeroconf / mdns discovery service with

tools like Avahi (GNU/Linux) or Bonjour (Mac).

40 Keysight N777-C Series Tunable Laser Family User’s Guide

N777-C User Interface

Getting Started 2

Keysight offers the N777-C Tunable Laser Source instruments with an optional display. Figure 12 shows the user interface accessed in the instrument’s display:

Figure 12 N777-C Instrument User Interface

For details on the interface and how to access and use it, see Chapter ,

“N777-C Instrument’s Front Panel Display,” on page 85.

Keysight N777-C Series Tunable Laser Family User’s Guide 41

2 Getting Started

Figure 13 shows the web interface of the N777-C (Option D00) non-display

instruments where the user interface can be used in a web browser on your computer.

Figure 13 N777-C Web Interface

For details on the web interface and how to use it, see Chapter , “N777-C

Web Interface Reference,” on page 59.

42 Keysight N777-C Series Tunable Laser Family User’s Guide

Keysight N777-C Series Tunable Laser Family

User’s Guide

3 Definition of Terms

General Definitions / 44 Absolute wavelength accuracy (continuous sweep mode) / 45 Absolute wavelength accuracy (stepped mode) / 45 Dynamic power reproducibility (continuous sweep mode) / 45 Dynamic relative power flatness (continuous sweep mode) / 46 Effective linewidth / 46 Linewidth / 47 Maximum output power / 47 Mode-hop free tunability / 48 Operating temperature and humidity / 48 Output isolation / 48 Polarization extinction ratio / 48 Power flatness versus wavelength / 49 Power linearity / 50 Power repeatability / 50 Power stability / 51 Relative intensity noise (RIN) / 51 Relative wavelength accuracy (continuous sweep mode) / 52 Relative wavelength accuracy (stepped mode) / 52 Return loss / 53 Side-mode suppression ratio / 53 Signal to source spontaneous emission (SSE) ratio / 54 Signal to total source spontaneous emission ratio / 55 Wavelength range / 55 Wavelength repeatability (continuous sweep mode) / 55 Wavelength repeatability (stepped mode) / 56 Wavelength resolution / 57 Wavelength stability / 57

3 Definition of Terms

NOTE

Definition of Terms

General Definitions

This section defines terms that are used in this document and in the data sheet.

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

Constant Temperature

Where required, is a stable operating temperature within ±1 K.

Logged wavelength

This is the wavelength measured and recorded by the internal wavelength meter during a sweep at the corresponding trigger signal. This recorded wavelength can be read with the logging function.

The logged wavelength positions during a sweep depend on environmental conditions and may differ slightly between repeated sweeps.

Stepped mode

In stepped mode the tunable laser source is operated statically, so that a user's measurement is made at a fixed wavelength of the tunable laser source. When tuning to a new wavelength, the static specifications are valid after completion of the tuning operation.

Continuous sweep mode

In continuous sweep mode the tunable laser source is operated dynamically, so that a user's measurement is made while the wavelength of the tunable laser source changes in a defined way (given by start wavelength, end wavelength and sweep speed). During a continuous sweep the dynamic specifications and the

44 Keysight N777-C Series Tunable Laser Family User’s Guide

“Logged wavelength“ apply.

Absolute wavelength accuracy (continuous sweep mode)

Definition of Terms 3

The maximum difference between the wavelength in “Continuous sweep mode“. Wavelength is defined as wavelength in vacuum.

Figure 14 Absolute wavelength accuracy (continuous sweep mode)

Conditions: As specified. No mode-hop.

Absolute wavelength accuracy (stepped mode)

The maximum difference between the displayed wavelength and the actual wavelength of the tunable lase source. Wavelength is defined as wavelength in vacuum.

Conditions: Constant power level. Other conditions as specified.

Measurement: Using a wavelength meter, averaging time

“Logged wavelength“ and the actual

≥ 1s.

Dynamic power reproducibility (continuous sweep mode)

Specifies the random uncertainty in reproducing the output power at the same actual wavelength in different sweeps. It is expressed as ± half the span between the maximum and minimum of all actual output powers.

Keysight N777-C Series Tunable Laser Family User’s Guide 45

3 Definition of Terms

Figure 15 Dynamic power reproducibility (continuous sweep mode)

Conditions: Uninterrupted tunable laser source output power, constant temperature,

no mode-hop. Other conditions as specified.

Dynamic relative power flatness (continuous sweep mode)

The high frequency part of the dynamic power flatness, obtainable by referencing the power measured at high sweep speed to the power measured at low sweep speed.

Conditions: Uninterrupted tunable laser source output power, constant power setting,

constant temperature, no mode-hop. Other conditions as specified.

Measurement: Reference sweep speed value 0.5 nm/s.

Effective linewidth

The time-averaged 3 dB width of the optical spectrum, expressed in Hertz.

Conditions: Coherence control on. Other conditions as specified.

Measurement: Using a heterodyning technique: The output of the laser under test is

mixed with another laser of the same type on a wide bandwidth photo-detector. The electrical noise spectrum of the photo-detector current is measured with a Lightwave signal analyzer, and the line-width calculated from the heterodyne spectrum. (Lightwave signal analyzer settings: resolution bandwidth 1 MHz, video bandwidth 10 kHz, sweep time 20 ms, single scan).

46 Keysight N777-C Series Tunable Laser Family User’s Guide

Definition of Terms 3

Linewidth

The 3 dB width of the optical spectrum, expressed in Hertz.

Conditions: Coherence control off. Other conditions as specified.

Measurement: Using a self-heterodyning technique: The output of the laser under test is

sent through a Mach-Zehnder interferometer in which the length difference of the two arms is longer than the coherence length of the laser. The electrical noise spectrum of the photo-detector current is measured using a Lightwave signal analyzer or Keysight Optical Modulation Analyzer, and the linewidth calculated from the heterodyne spectrum.

Alternatively, Using a heterodyning technique: The output of the laser under test is mixed on a wide bandwidth photo-detector with another laser of the same type or with a laser with a line-width much lower than the laser to be measured. The electrical noise spectrum of the photo-detector current is measured using a Lightwave signal analyzer or Keysight Optical Modulation Analyzer, and the linewidth calculated from the heterodyne spectrum.

Maximum output power

The maximum achievable output power of the tunable laser source and the maximum output power for which the tunable laser source specifications apply.

Figure 16 Maximum Output Power vs Wavelength, Maximum

Conditions: As specified.

Keysight N777-C Series Tunable Laser Family User’s Guide 47

Flat Output Power vs Wavelength

3 Definition of Terms

NOTE

Mode-hop free tunability

Operating temperature and humidity

Measurement: Using a power meter at the end of a 2 m single-mode fiber patchcord.

Specifies the wavelength range for which no abrupt wavelength change occurs in Stepped mode.

The ambient temperature range and humidity range of the tunable laser source for which the specifications apply.

If the instrument is rack-mounted, the temperature and humidity within the rack apply.

48 Keysight N777-C Series Tunable Laser Family User’s Guide

Output isolation

The insertion loss of the built-in isolator in the backward direction.

Measurement: This characteristic cannot be measured from outside the instrument. It is

based on known isolator characteristics.

Polarization extinction ratio

Specifies the ratio of the optical power in the slow axis of a connected polarization-maintaining fiber to optical power in the fast axis, expressed in dB

Measurement: Using a polarization analyzer at the end of a polarization-maintaining

patchcord, by sweeping the wavelength to create circular traces on the Poincaré sphere. Calculate the polarization extinction ratio from the diameters of these circles.

Definition of Terms 3

Figure 17 Circular traces on the Poincaré sphere used to calculate

polarization extinction ratio.

Power flatness versus wavelength

Specifies ± half the span (in dB) between the maximum and the minimum actual power levels of the tunable laser source when changing the wavelength.

Figure 18 Power flatness vs. wavelength.

Conditions: Uninterrupted tunable laser source output power, constant power setting,

constant temperature. Other conditions as specified.

Keysight N777-C Series Tunable Laser Family User’s Guide 49

3 Definition of Terms

NOTE

Power linearity

When measuring the ratios (in dB) between the displayed power level and the actual power level for different output power levels of the tunable laser source, the power linearity is ± half the difference between the maximum and the minimum value of all ratios.

Figure 19 Power linearity.

Conditions: Uninterrupted tunable laser source output power, constant wavelength

setting, constant temperature. Other conditions as specified.

Power repeatability

The uncertainty in reproducing the power level after changing and re-setting the power level. The power repeatability is ± half the span between the highest and lowest actual power.

Conditions: Uninterrupted tunable laser source output power, constant wavelength

setting, constant temperature. Other conditions as specified.

The long-term power repeatability can be obtained by taking the power repeatability and power stability into account.

50 Keysight N777-C Series Tunable Laser Family User’s Guide

Power stability

Definition of Terms 3

Specifies the change of the power level of the tunable laser source over time, expressed as ± half the span (in dB) between the highest and lowest actual power.

Figure 20 Power stability.

Conditions: Time span as specified. Uninterrupted tunable laser source output power,

constant wavelength and power level settings, constant temperature. Other conditions as specified.

Relative intensity noise (RIN)

Specifies the ratio between the mean-square of the optical power fluctuation amplitude bandwidth B, and the square of the average optical power P

RIN, if expressed as "dB/Hz", is calculated by:

Keysight N777-C Series Tunable Laser Family User’s Guide 51

ΔP

within a specified frequency range f and for

f,B

avg

3 Definition of Terms

Relative wavelength accuracy (continuous sweep mode)

Conditions: As specified.

Measurement: Using a Lightwave signal analyzer and bandwidth set to 3 MHz.

When measuring the differences between the actual and Logged wavelength in Continuous sweep mode, the dynamic wavelength accuracy is ± half the span between the maximum and the minimum value of all differences.

Figure 21 Relative wavelength accuracy (continuous sweep mode).

Conditions: As specified. No mode-hop.

Relative wavelength accuracy (stepped mode)

When randomly changing the wavelength and measuring the differences between the displayed and the actual wavelength, the relative wavelength accuracy is ± half the span between the maximum and the minimum value of all differences.

52 Keysight N777-C Series Tunable Laser Family User’s Guide

Definition of Terms 3

Figure 22 Relative wavelength accuracy.

Conditions: Uninterrupted tunable laser source output power, constant power setting,

constant temperature. Other conditions as specified.

Measurement: Using a wavelength meter, averaging time

Return loss

Specifies the ratio of the optical power incident to the tunable laser source output port at the wavelength set on the tunable laser source, to the power reflected from the tunable laser source output port.

Conditions: Tunable laser source output off.

Side-mode suppression ratio

The ratio of optical power in the main mode to the optical power of the highest sidemode, expressed in dB:

Conditions: As specified.

≥ 1s.

Keysight N777-C Series Tunable Laser Family User’s Guide 53

3 Definition of Terms

Signal to source spontaneous emission (SSE) ratio

Measurement: Using the Lightwave signal analyzer, by analyzing the heterodyning

between the main signal and the highest side mode within 0.1 GHz to 6GHz.

Specifies the ratio between signal power and maximum spontaneous emission (SSE) power. The SSE power is determined in a specified bandwidth within a ±3 nm window around the signal wavelength, where ±1 nm around the signal wavelength are excluded, expressed in dB per specified bandwidth.

Figure 23 Signal to source spontaneous emission ratio.

Conditions: Output power as specified. Other conditions as specified.

Measurement: Using an optical spectrum analyzer (OSA) at 0.5 nm resolution bandwidth

(to address the possibility of higher SSE within a narrower bandwidth), then extrapolated to 1 nm bandwidth. For the low-SSE output, if applicable, with a fiber Bragg grating inserted between the tunable laser source and the OSA to suppress the signal, thereby enhancing the dynamic range of the OSA.

54 Keysight N777-C Series Tunable Laser Family User’s Guide

Signal to total source spontaneous emission ratio

The ratio of signal power to total spontaneous emission power within, expressed in dB. The total spontaneous emission power is measured over the specified Wavelength range.

Figure 24 Signal to total source spontaneous emission ratio.

Definition of Terms 3

Conditions: Output power as specified. Other conditions as specified.

Measurement: Using an optical spectrum analyzer, by integrating the source

spontaneous emission and excluding the remnant signal. For the low-SSE output, if applicable, with a fiber Bragg grating inserted between the tunable laser source and the OSA to suppress the signal, thereby enhancing the dynamic range of the OSA.

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

Wavelength range

The range of wavelengths for which the specifications apply (if not otherwise stated).

Wavelength repeatability (continuous sweep mode)

The random uncertainty of the nominal wavelength of the tunable laser source at any fixed actual wavelength in repeated sweeps. The nominal wavelength of the tunable laser source is derived from the (discrete)

Keysight N777-C Series Tunable Laser Family User’s Guide 55

3 Definition of Terms

NOTE

Logged wavelength by interpolation. The repeatability is expressed as ±

half the span between the maximum and the minimum value of all nominal values.

Figure 25 Wavelength repeatability (continuous sweep mode).

Conditions: As specified. No mode-hop.

Measurement: Using an optical power meter and by performing repeated spectral loss

measurement on a stable absorption peak from a reference component, then analyzing the variation of the determined (interpolated) wavelength of the peak.

Wavelength repeatability (stepped mode)

The random uncertainty in reproducing a wavelength after changing and re-setting the wavelength. The wavelength repeatability is ± half the span between the maximum and the minimum of all actual values of this wavelength.

Conditions: Uninterrupted tunable laser source output power, constant power level,

constant temperature. Other conditions as specified.

Measurement: Using a wavelength meter, averaging time

≥ 1s.

The wavelength repeatability of the low-SSE output (if applicable) is the same as the wavelength repeatability of the high power output (guaranteed by design).

56 Keysight N777-C Series Tunable Laser Family User’s Guide

Definition of Terms 3

NOTE

The long-term wavelength repeatability can be obtained by taking the wavelength repeatability and wavelength stability into account.

Wavelength resolution

The smallest selectable wavelength increment or decrement.

Wavelength stability

Specifies the change of the actual wavelength of the tunable laser source over time, expressed as ± half the span between the maximum and minimum of all wavelengths.

Conditions: Time span as specified, uninterrupted tunable laser source output power,

constant wavelength and power level settings, constant temperature. Other conditions as specified.

Measurement: Using a wavelength meter, averaging time

Keysight N777-C Series Tunable Laser Family User’s Guide 57

≥ 1s.

Keysight N777-C Series Tunable Laser Family

User’s Guide

4 N777-C Web

Interface Reference

N777-C Web Interface / 60 Controlling N777-C Instruments / 62 How to Use Auxiliary Functions / 74

4 N777-C Web User Interface Reference

N777-C Web Interface

Figure 26 shows the N7776C web interface with various tabs highlighted.

The same web interface is applicable for N7778/79C instruments.

Figure 26 N7776C Web Interface

The N777-C web interface has the various tabs that help the user to control the instruments:

• Home – This tab displays the various instrument settings. For details, refer How to Get Current Instrument Settings? on page 74.

• Control Instrument – This tab allows you to set the parameters to control the instrument. For details, refer to Controlling N777-C

Instruments on page 62.

• Get Image – This tab allows you to capture a screen of the Control Instrument window. The image is saved in PNG format in your PC. For details, see How to Capture an Image of the Graph? on page 75.

60 Keysight N777-C Series Tunable Laser Family User’s Guide

N777-C Web User Interface Reference 4

• Configure LAN – This tab displays the current LAN configuration. In addition, this tab also allows you to edit the current LAN configuration. For details, refer to How to Configure LAN? on page 80.

• Help – This tab opens the instrument help.

Keysight N777-C Series Tunable Laser Family User’s Guide 61

4 N777-C Web User Interface Reference

Controlling N777-C Instruments

Control Instrument Tab

The Control Instrument tab is used to control the N777-C instruments:

The Control Instrument tab provides the following features:

Display Wavelength and Power

Displays the instrument’s current wavelength and power.

62 Keysight N777-C Series Tunable Laser Family User’s Guide

Changing Wavelength, Power and Units

Left/Right Arrows

Up/Down Arrows

Changing Wavelength

Changing Unit

Allows you to change the instrument’s current wavelength, power and their respective units. The procedure for changing wavelength, power and their units are similar. The following example provides steps to change the wavelength and its unit.

1 Click on the wavelength button. 2 Use the left or right arrows to move the position of the cursor pointer

either to the left or right. 3 Use the up or down arrows to increase or decrease the wavelength. 4 Click on the unit button to change the unit. The allowed units for

Wavelength are nm and THz. The allowed units for Power are mW

and dBm.

N777-C Web User Interface Reference 4

Wavelength Vs. Power Graph

The Control Instrument tab displays a graph that shows the relationship between the wavelength and power. The power is represented by x axis while the Y axis represents the wavelength.

Keysight N777-C Series Tunable Laser Family User’s Guide 63

4 N777-C Web User Interface Reference

You can click on the graph to modify the wavelength and power. The blue curve on the graph denotes the excessive power curve. Setting an output power above the maximum power curve is indicated with EXP on the power display. For details, see How to Avoid Access Power? on page 66.

64 Keysight N777-C Series Tunable Laser Family User’s Guide

Working with Markers

To add a marker, double-click at a point on the graph where you want to add the marker. A small blue circle on that point denotes the marker. You are allowed to set multiple markers. Hovering the cursor over the marker causes the wavelength and power display.

To save the marker, click on the Save Current Markers option.

To remove all saved markers, click on the Remove All Marker option.

How to set Wavelength?

How to change the Wavelength

There are three ways to set the wavelength of the Tunable Laser.

• You can set the wavelength directly on clicking the Wavelength button,

•You go the Settings > Measurement Settings and then set the

• You can click on the graph to set a wavelength.

Wavelength Range

Every Tunable Laser instrument has a specified wavelength range. This range is available for all Tunable Laser instruments. See the Laser Safety

Information on page 15 to find your instrument’s specified range.

Every Tunable Laser instrument has a permitted wavelength range. This range is greater than the specified range. The permitted wavelength range varies for each Tunable Laser instrument. You can set the wavelength to any value within the permitted wavelength range.

N777-C Web User Interface Reference 4

see Changing Wavelength, Power and Units on page 63.

wavelength, or

How to Set Power?

How to change the power

There are three ways of changing the power:

• You can set the power directly on clicking the Power button, see

Changing Wavelength, Power and Units on page 63.

•You go the Settings > Measurement Settings and then set the power,

• You can click on the graph to set a power.

How to Set the Power Unit

Pressing the unit button allows you to switch either mW or dBm as the units in which power is displayed.

What are the Power Units?

Watts (W) are the SI unit for power measurement.

You can also measure power in dBm. Values displayed in these units are derived from measurement in Watts.

By selecting dBm, the following calculation is made:

Keysight N777-C Series Tunable Laser Family User’s Guide 65

4 N777-C Web User Interface Reference

How to Avoid Access Power?

Where,

is the power value displayed in dBm, and

dBm

is the input signal level in Watts.

input

Power, in units of dBm, is measured relative to 1 mW, it is an absolute power measurement.

If the text EXP is displayed in power of a Tunable Laser channel, you have set an output power level that is larger than the laser diode can produce at the selected wavelength.

To avoid this you can:

• reduce the optical output power,

•click Set Pmax in the Measurement Setting option to select the

highest permissible power for the selected.

•click Set Pmax/Sweep to select the highest permissible power for the

selected wavelength sweep.

How to Perform a Wavelength Sweep?

What is a Wavelength Sweep?

A wavelength sweep is performed when the instrument changes the optical wavelength of the optical output across a user-defined wavelength range. You can use a wavelength sweep to measure the wavelength-dependent loss of an optical component.

66 Keysight N777-C Series Tunable Laser Family User’s Guide

How to Set the Wavelength Sweep?

The Sweep Parameters

N777-C Web User Interface Reference 4

These are the parameters for the wavelength sweep:

• Sweep Mode - see How to Perform a Sweep? on page 69,

• Repeat mode - see How to Set the Repeat Mode? on page 68.

• Sweep Speed - the speed of a continuous sweep,

• Cycles - the number of times the sweep is repeated,

• Dwell - the amount of time spent at the wavelength during each step,

for a stepped sweep

• Sweep Start - the wavelength at which the sweep begins,

• Sweep Stop - the wavelength at which the sweep ends,

• Sweep Step - the size of the change in the wavelength for each step of

a sweep,

• Run/Stop Sweep - to run and start the sweep.

Keysight N777-C Series Tunable Laser Family User’s Guide 67

4 N777-C Web User Interface Reference

NOTE

For a Continuous sweep, Step sets the wavelength interval between output triggers, if you have set Output Trigger Mode to Step Finished,

How to Use Output Triggering on page 71.

see

How to Set the Repeat Mode?

68 Keysight N777-C Series Tunable Laser Family User’s Guide

Figure 27 The Parameters for a Stepped Wavelength Sweep

The Repeat Mode determines how the instrument performs a multi-cycle

sweep.

• Select Two way, if you want to start every odd sweep cycle at [λ Start]

and to start each even sweep cycle at [λ Stop].

• Select Oneway, if you want to start every sweep cycle at [λ Start] and to

end every sweep cycle at [λ Stop].

Figure 28 illustrates how these modes work for a three-cycle wavelength

sweep.

N777-C Web User Interface Reference 4

NOTE

Figure 28 Repeat Modes

How to Set the Maximum Power for the Sweep Range?

Pressing Set Pmax/Sweep sets the power to the maximum for the selected sweep range. Pressing Set Pmax/Sweep ensures the power will be constant for the whole sweep.

How to Perform a Sweep?

There are three sweep modes:

• Stepped - which dwells at wavelengths that are separated by a certain

step size,

• Continuous - which sweeps continually at the speed you set, and

• Manual - which you can run each step manually.

You cannot turn the laser off by pressing the Active hardkey on the Tunable Laser front panel, while a wavelength sweep is running.

You can press Stop and, then, press the Active hardkey on the Tunable Laser front panel, to turn off the laser.

Keysight N777-C Series Tunable Laser Family User’s Guide 69

4 N777-C Web User Interface Reference

CAUTION

How to Use Triggers?

How to Set the Trigger Configuration

The N777-C Tunable Laser instruments allow you to trigger the instrument to perform tasks and to output trigger signals to external measurement instruments.

The trigger level at the external trigger connectors is by default active high, this means when a trigger rises above the high TTL level (rising edge), a trigger is accepted.

You can use the Trigger Config drop-down menu to select the triggering mode. The following trigger configuration modes are available:

1 Disabled - select this mode if you do not want to use triggering. In this

case input and output connectors are disabled. 2 Default - select this mode if you want to enable the trigger connectors.

In this case input and output connectors are active. 3 Passthrough - select this mode if you want an input trigger to

automatically generate an output trigger. This allows you to trigger

another instrument almost simultaneously.

70 Keysight N777-C Series Tunable Laser Family User’s Guide

How to Use Input Triggering

You can configure your N777-C Tunable Laser instrument to perform certain tasks when you apply a trigger to the Input Trigger Connector.

A maximum of 5 V can be applied as an external voltage to the Input Trigger connector.

Do not apply an external voltage to these connectors.

To set your instrument’s Input Trigger Configuration:

NOTE

1From the Settings > Measurement Settings and select Trigg er. 2 Use the drop-down menu to select the Input Trigger. The following

input trigger options are available:

• Ignore, input triggers are ignored.

• Next Step, an input trigger will cause the next step of a stepped

sweep to be performed.

• Run Sweep, an input trigger will start a single sweep cycle.

3 You can generate input triggers in any of the following ways:

• applying a trigger to the Input Trigger Connector on the rear panel

of your instrument,

• setting Trigger Configuration to Loopback so that an output trigger

automatically generates an input trigger, or

• using the :TRIGger1 command, see your Programming Guide.

How to Use Output Triggering

You can configure your Tunable Laser instrument to output a trigger when the instrument performs certain tasks.

To set your instrument’s Output Trigger Configuration:

1From the Settings > Measurement Settings and select Trigg er. 2 Use the drop-down menu to select the Output Trigger. The following

output trigger options are available:

• Disabled, the output trigger mode is disabled.

• Step Finished, a trigger is output after every step of a sweep

finishes.

• Sweep Finished, a trigger is output after a sweep cycle finishes.

• Sweep Started, a trigger is output after a sweep cycle starts.

N777-C Web User Interface Reference 4

If you choose Step Finished and a Continuous sweep, the wavelength interval between hardware triggers is set by the Step parameter, although, the sweep is not stepped.

How to set Modulation?

Keysight N777-C Series Tunable Laser Family User’s Guide 71

4 N777-C Web User Interface Reference

The following modulation modes are available:

• OFF - No modulation

• Coherence - You can use coherence control to increase the line width of the optical signal output from your Tunable Laser instrument.

Enabling the coherence control increases the line width of the optical output signal to between 50 and 500 MHz (typically). Coherence control greatly reduces interference effects and therefore improves the power stability in sensitive test setups.

The N777-C instruments also allow adjustment of the line width broadening with the "Coherence Level" setting. A level of 100% corresponds to minimal broadening. The default level is usually a good setting.

• Wavelength Locking - You can choose wavelength locking as the modulation source, so the change in output wavelength is roughly proportional to the voltage you apply to the input BNC connector on the front panel of your Tunable Laser instrument.This enables you to fine tune the output wavelength within a limited wavelength range.

Wavelength locking may exhibit some hysteresis effects. The wavelength change may differ slightly when you increase voltage from when you decrease voltage.

If you modulate the input signal, the amplitude of the wavelength change of the modulated optical output reduces with increasing modulation frequency.

How to Lock/Unlock the Instrument?

Locking the instrument avoids to turn on the laser of the tunable laser instruments. This helps in avoiding accidents that are caused due to laser. To lock a device;

1 On the Control Instrument page, click to Settings > Measurement

Settings and then go to Device Locked option.

72 Keysight N777-C Series Tunable Laser Family User’s Guide

2Click on the Device Locked button the lock or unlock the device.

NOTE

Laser OFF Laser ON

Please note that you will be not able to open the device shutter or turn on the laser until the device is locked.

How to Turn ON/OFF the Laser?

To turn ON/OFF the laser; 1 On the Control Instrument page, click to Settings > Measurement

Settings and then go to Shutter Open option.

2Click on the Shutter Open button the turn ON/OFF the high-power

laser. Ensure that your device is unlocked.

N777-C Web User Interface Reference 4

3 Additionally, you can also click on the Laser ON/OFF button available

on the Control Instrument page.

Keysight N777-C Series Tunable Laser Family User’s Guide 73

4 N777-C Web User Interface Reference

NOTE

How to Use Auxiliary Functions

How to Get Current Instrument Settings?

The Home tab on the N777-C web interface displays the current instrument settings.

This tab displays the following settings:

• Description – Displays the instrument description such as instrument’s model no., serial no., firmware version and description of the current instrument.

• VISA Instrument Address – Displays VISA instrument addresses of the current instrument.

• LAN Details – Displays LAN configuration details of the current instrument.

Please note that the Home tab does not allow the user to change the displayed instrument settings.

74 Keysight N777-C Series Tunable Laser Family User’s Guide

How to Identity a Particular instrument?

NOTE

Sometimes, you have many instruments mounted on the rack. In this situation, it becomes difficult to identify a particular instrument which are currently connected.

To identify a particular instrument, select the check-box Enable front

panel identification indicator available on the N777-C Home tab. The Status LED on the front panel of the connected instrument will start

flashing.

How to Capture an Image of the Graph?

The Get Image tab on the N777-C web interface allows you to capture the current screen of the Control Instrument tab and save it as a PNG image. The captured image is saved in the “Downloads” folder.

N777-C Web User Interface Reference 4

You can only capture the screen if you are in the Control Instrument tab.

How to Save/Recall the Web Interface Settings?

The Save/Recall tab on the N777-C web interface allows you to save and recall the web interface settings.

Keysight N777-C Series Tunable Laser Family User’s Guide 75

4 N777-C Web User Interface Reference

Logging In/Out of the N777-C Web Interface

To perform the save/recall operation: 1Click on the Save/Recall tab. 2 To save a file, click on Export button. The web interface settings will be

saved as an XML file in your PC.

3 To recall a previously saved file, click on Upload your XML file here

button. A Windows Open dialog will appear. Locate the target file and click Open. The settings will be loaded in the instrument.

The login screen allows the authorized users to control the N777-C instruments. When the users type in their password and click Enter, their credentials are validated and if correct they are logged in.

If you want to create a new password or change an existing password, click on Change Password button. For details, see How to Create/Change

the Password? on page 77.

To log out the N777-C web interface, click on Log out icon available on the

top right of the web interface.

76 Keysight N777-C Series Tunable Laser Family User’s Guide

How to Create/Change the Password?

NOTE

The password is used for logging in to the web page to control the N777-C instrument. To create or change a password;

1Click the Password Options icon available on the top right of the

N777-C web interface. You see a Change Password box requesting you to enter the password.

N777-C Web User Interface Reference 4

2 Enter the current password (the default password is blank). 3 Enter the new password. 4Click the Change Password button. The password will be changed.

What If You Forget Your Password?

If you forget your password, please follow the instructions to reset the LAN button. See The LAN Reset button on page -34.

How to perform Realignment?

Realignment realigns the laser cavity. You should use Realignment if you have already tried to reactivate the laser and to reduce power, and this has been unsuccessful.

To get the specified performance, ensure that the warm-up time has passed before starting realignment.

Keysight N777-C Series Tunable Laser Family User’s Guide 77

4 N777-C Web User Interface Reference

Lambda Zeroing

To realign the laser cavity: 1Go to Settings and click Realign.

The following Realign Device dialog will appear:

2Click Realign System button. 3 Wait until the realign process completes. This process may take about

1 minute.

Performing a Lambda Zero re-calibrates the optical wavelength. This wavelength may drift due to a change in temperature and other environmental conditions. The regulated wavelength and wavelength logging data remain accurate, but the sweep may be offset from the intended range.

A Lambda Zero is automatically performed when the instrument boots or when an realignment is performed.

It is advisable to run this after warm-up. Also, periodic use, perhaps daily, during continuous operation or if sweeps are missing points is recommended.

To perform a wavelength zero: 1Go to Settings and click Lambda Zeroing.

The following Lambda Zeroing dialog will appear:

78 Keysight N777-C Series Tunable Laser Family User’s Guide

Update Rate

N777-C Web User Interface Reference 4

2Click Lambda Zero button. 3 This proves may take several minutes. This time depends on how much

the wavelength of the instrument has drifted since the last Lambda Zero was performed. Please wait until the Lambda Zeroing is completed.

You can use the Update Rate feature to set the refresh rates in milliseconds for the instrument settings and arrow used in the Control Instrument tab.

To perform an update rate: 1Go to Settings and click Update Rate.

An Update Rate dialog will appear:

2 Enter the new refresh rates in milliseconds for the instrument settings

and arrow.

3Click on Save button.

Keysight N777-C Series Tunable Laser Family User’s Guide 79

4 N777-C Web User Interface Reference

NOTE

Reboot Device

The new refresh rates will only be effective for the current session.

An instrument reboot is required if it becomes unresponsive or returns errors. To perform a reboot:

1 Go to Settings and click Reboot. A Reboot Device dialog will appear:

2Click on the Reboot System button. This action will restart the

instrument and take at least 180 seconds. Please wait until the reboot process is completed.

How to Configure LAN?

Show the Current LAN Settings

The Configure LAN tab on the N777-C web interface displays the currently used LAN settings. It display the following networking parameters:

• IP address configuration

• IP address

• Subnet mask

•Default gateway

80 Keysight N777-C Series Tunable Laser Family User’s Guide

•DNS server(s)

WARNING

•Hostname

•Domain

Edit LAN Settings

The Configure LAN tab also allows you to edit the currently used LAN settings. To do so,

1Click on the Edit button. The Edit Network Configuration page will

appear as shown in the figure below:

N777-C Web User Interface Reference 4

Your connection to the instrument may be broken after executing either of the operations below. If so, reconnect to the instrument using the new hostname or IP address.

Keysight N777-C Series Tunable Laser Family User’s Guide 81

4 N777-C Web User Interface Reference

NOTE

Reset Network Configuration

Enter the descriptions for the following LAN configuration parameters:

• Instrument identification

• IP address configuration

• DNS server address configuration

For IP address and DNS server configuration, you can select the Use Automatic Configuration check-box to automatically select the IP address and DNS server.

Once, the changes are done, click on Apply Changes button.

It can take up to 30 seconds for changes to these settings to take effect. You may need to refresh the Configure LAN page after 30 seconds to see the updated settings. Changes in host name and description require reboot or LAN restart to take effect.

The Configure LAN tab also allows you to reset all LAN parameters to the factory default. To do so;

1Click the Advance Options button available on Configure LAN tab. The

Advance Network Options page will appear.

82 Keysight N777-C Series Tunable Laser Family User’s Guide

N777-C Web User Interface Reference 4

WARNING

2Click on the Reset button to reset all LAN parameters to the factory

default.

Your browser connection to the instrument may be broken after executing the reset network configuration operation. If so, reconnect to the instrument using the new hostname or IP address.

Keysight N777-C Series Tunable Laser Family User’s Guide 83

Keysight N777-C Series Tunable Laser Family

User’s Guide

5 N777-C Instrument’s

Front Panel Display

N777-C Instrument’s Front Panel Display / 86 Controlling N777-C Instruments / 88

5 N777-C Instrument’s Front Panel Display

N777-C Instrument’s Front Panel Display

Figure 29 shows the N777-C instrument’s front panel display:

Figure 29 N7776C User Interface

The N777-C instrument’s front panel provides the following elements:

Elements Caption Description

Control Instrument This button opens the Control Instrument window which allows you to set

More INFORMATION

86 Keysight N777-C Series Tunable Laser Family User’s Guide

the parameters to control the instrument. For details, refer to

Controlling N777-C Instruments on page 88.

This button opens More Information window which displays the instrument settings. For details, refer How to Get Current Instrument

Settings?

on page 101

Elements Caption Description

N777-C Instrument’s Front Panel Display 5

Configure LAN This button opens the Configure LAN window which displays the current

LAN configuration and allows you to edit the current LAN configuration. For details, refer to How to Configure LAN? on page 103

Help This button opens the instrument’s help.

Home This button navigates you to the home screen (the default screen).

Keysight N777-C Series Tunable Laser Family User’s Guide 87

5 N777-C Instrument’s Front Panel Display

Controlling N777-C Instruments

Control Instrument Window

To access the instrument settings and to manually control the instrument, click Control Instrument present on the user interface.

The following Control Instrument window will appear:

88 Keysight N777-C Series Tunable Laser Family User’s Guide

The Control Instrument window provides the following features:

Display Wavelength and Power

Displays the instrument’s current wavelength and power.

N777-C Instrument’s Front Panel Display 5

Changing Wavelength, Power and Units

Keysight N777-C Series Tunable Laser Family User’s Guide 89

5 N777-C Instrument’s Front Panel Display

1Click on the Wavelength button. The on-screen numeric keypad will

appear. Use this keypad to enter the wavelength values.

2 Use the left (<<) or right (>>) arrow buttons to move the position of the

cursor pointer either to the left or right. 3 Use the (+) or (-) buttons to increase or decrease the wavelength value. 4 Once done, click on Done button. 5 The unit button is a toggle button. Click on this button to change the

unit. The allowed units for Wavelength are nm and THz. The allowed

units for Power are mW and dBm.

Wavelength Vs. Power Graph

The Control Instrument window displays the relationship between the wavelength and power through a graph. The x-axis represents the wavelength and the Y axis represents the power.

The white curve on the graph denotes the maximum power curve. Setting an output power above the maximum power curve is indicated with EXP on the power display. For details, see How to Avoid Excessive Power? on page 93

90 Keysight N777-C Series Tunable Laser Family User’s Guide

N777-C Instrument’s Front Panel Display 5

The graph also provides the zoom functionality. The Zoom In button allows you to enlarge the graph on full screen to view more details.

The Zoom Out button allows you to reduce the graph to its normal size.

How to set Wavelength?

How to change the Wavelength

You can set the wavelength value by directly clicking on the Wavelength button. For details, see Changing Wavelength, Power and Units on page 89.

Every Tunable Laser instrument has a specified wavelength range. This range is available for all Tunable Laser instruments. See the Laser Safety Information to find your instrument’s specified range.

Keysight N777-C Series Tunable Laser Family User’s Guide 91

5 N777-C Instrument’s Front Panel Display

How to Set the Wavelength Unit?

What are the Wavelength Unit?

How to Set Power?

How to change the power

How to Set the Power Unit

Pressing the unit button allows you to switch either nm or THz as the units in which power is displayed.

The SI unit of wavelength measurement is meter usually denoted as m.

You can set the power value by directly clicking on the Power button. For details, see Changing Wavelength, Power and Units on page 89.

Pressing the unit button allows you to switch either mW or dBm as the units in which power is displayed.

What are the Power Units?

Watts (W) are the SI unit for power measurement.

You can also measure power in dBm. Values displayed in these units are derived from measurement in Watts.

By selecting dBm, the following calculation is made:

Where,

is the power value displayed in dBm, and

dBm

is the input signal level in Watts.

input

Power, in units of dBm, is measured relative to 1 mW, it is an absolute power measurement.

92 Keysight N777-C Series Tunable Laser Family User’s Guide

How to Avoid Excessive Power?

If the text EXP is displayed in power of a Tunable Laser channel, you have set an output power level that is larger than the laser diode can produce at the selected wavelength.

To avoid this you can:

• reduce the optical output power,

•click Set P

power for the selected wavelength.

•click Set P

selected wavelength sweep.

How to Perform a Wavelength Sweep?

What is a Wavelength Sweep?

max

N777-C Instrument’s Front Panel Display 5

in the Setting option to select the highest permissible

/Sweep to select the highest permissible power for the

How to Set the Wavelength Sweep?

The wavelength sweep can be set up through the Sweep VIEW tab.

Keysight N777-C Series Tunable Laser Family User’s Guide 93

5 N777-C Instrument’s Front Panel Display

NOTE

These are the parameters for the wavelength sweep:

• Sweep Mode - see How to Perform a Sweep? on page 96,

• Repeat Mode - see How to Set the Repeat Mode? on page 95,

• Sweep Speed - the speed of a continuous sweep,

• Cycles - the number of times the sweep is repeated,

• Dwell - the amount of time spent at the wavelength during each step,

for a stepped sweep

• Sweep Start - the wavelength at which the sweep begins,

• Sweep Stop - the wavelength at which the sweep ends,

• Sweep Step - the size of the change in the wavelength for each step of

a sweep,

• Run/Stop Sweep - to run and start the sweep.

For a Continuous sweep, Step sets the wavelength interval between output triggers, if you have set Output Trigger Mode to Step Finished,

How to Use Output Triggering on page 99.

see

94 Keysight N777-C Series Tunable Laser Family User’s Guide

Figure 30 The Parameters for a Stepped Wavelength Sweep

How to Set the Repeat Mode?

The Repeat Mode determines how the instrument performs a multi-cycle sweep.

• Select Two way, if you want to start every odd sweep cycle at [λ Start]

and to start each even sweep cycle at [λ Stop].

• Select Oneway, if you want to start every sweep cycle at [λ Start] and to

end every sweep cycle at [λ Stop].

N777-C Instrument’s Front Panel Display 5

Figure 31 illustrates how these modes work for a three-cycle wavelength

sweep.

Figure 31 Repeat Modes

Keysight N777-C Series Tunable Laser Family User’s Guide 95

5 N777-C Instrument’s Front Panel Display

NOTE

How to Set the Maximum Power for the Sweep Range?

Pressing Set P sweep range. Pressing Set P constant for the whole sweep.

How to Perform a Sweep?

There are three sweep modes:

• Stepped - which dwells at wavelengths that are separated by a certain

step size,

• Continuous - which sweeps continually at the speed you set, and

• Manual - which you can run each step manually.

/Sweep sets the power to the maximum for the selected

max

/Sweep ensures the power will be

max

You cannot turn the laser off by pressing the Active hardkey on the Tunable Laser front panel, while a wavelength sweep is running.

You can press Stop Sweep and, then, press the Active hardkey on the Tunable Laser front panel, to turn off the laser.

96 Keysight N777-C Series Tunable Laser Family User’s Guide

How to Use Triggers?

N777-C Instrument’s Front Panel Display 5

The N777-C Tunable Laser instruments allow you to trigger the instrument to perform tasks and to output trigger signals to external measurement instruments.

To view the Trigger window, click on the Trigger VIEW tab. The following window appears:

How to Set the Trigger Configuration

The trigger level at the external trigger connectors is by default active high, this means when a trigger rises above the high TTL level (rising edge), a trigger is accepted.

You can use the Trigger Config drop-down menu to select the triggering mode.

Keysight N777-C Series Tunable Laser Family User’s Guide 97

5 N777-C Instrument’s Front Panel Display

CAUTION

How to Use Input Triggering

The following trigger configuration modes are available: 1 Disabled - select this mode if you do not want to use triggering. In this

case input and output connectors are disabled. 2 Default - select this mode if you want to enable the trigger connectors.

In this case input and output connectors are active. 3 Passthrough - select this mode if you want an input trigger to

automatically generate an output trigger. This allows you to trigger

another instrument almost simultaneously.

98 Keysight N777-C Series Tunable Laser Family User’s Guide

You can configure your N777-C Tunable Laser instrument to perform certain tasks when you apply a trigger to the Input Trigger Connector.

A maximum of 5 V can be applied as an external voltage to the Input Trigger connector.

Do not apply an external voltage to these connectors.

To set your instrument’s Input Trigger Configuration: 1From the Control Instrument window, click Trigger VIEW tab. 2 Use the menu to select the Input Trigger. The following input trigger

options are available:

• Ignore, input triggers are ignored.

• Next Step, an input trigger will cause the next step of a stepped

sweep to be performed.

• Run Sweep, an input trigger will start a single sweep cycle.

3 You can generate input triggers in any of the following ways:

NOTE

• applying a trigger to the Input Trigger Connector on the rear panel

of your instrument,

• setting Trigger Configuration to Loopback so that an output trigger

automatically generates an input trigger, or

• using the :TRIGger1 command, see your N777-C Programming

Guide.

How to Use Output Triggering

You can configure your Tunable Laser instrument to output a trigger when the instrument performs certain tasks.

To set your instrument’s Output Trigger Configuration: 1From the Control Instrument window, click Trigger VIEW tab. 2 Use the menu to select the Output Trigger. The following output

trigger options are available:

• Disabled, the output trigger mode is disabled.

• Step Finished, a trigger is output after every step of a sweep

finishes.

• Sweep Finished, a trigger is output after a sweep cycle finishes.

• Sweep Started, a trigger is output after a sweep cycle starts.

N777-C Instrument’s Front Panel Display 5

If you choose Step Finished and a Continuous sweep, the wavelength interval between hardware triggers is set by the Step parameter, although, the sweep is not stepped.

Keysight N777-C Series Tunable Laser Family User’s Guide 99

5 N777-C Instrument’s Front Panel Display

How to set Modulation?

To view the Modulation window, click on the Modulation tab. The following window appears:

The following modulation modes are available:

• OFF - No modulation

• Coherence - You can use coherence control to increase the line width of the optical signal output from your Tunable Laser instrument.

100 Keysight N777-C Series Tunable Laser Family User’s Guide

Keysight N7776C, N7778C, N7779C User Manual

Specifications and Main Features

Frequently Asked Questions

User Manual

Safety Summary

Instrument Markings

South Korean Class A EMC Declaration

Compliance and Environmental Information

Declaration of Conformity

Contents

Overview

Laser Safety Information

Initial Safety Information for Keysight N777-C Family Lasers

Laser Safety Labels

Laser Safety Symbols

Operating Environment

Overview

Instrument Cooling

Operating Position

Handling the Instrument

Storage and Shipment

Carrying the Instrument

Rack Mount the Instrument

Obtaining Source Code

2 Getting Started

Initial Inspection

Initial Inspection

Claims and Repackaging

Return Shipments to Keysight Technologies

Deleting User Data

Power Supply Requirements

Line Power Requirements

Line Power Requirements

Line Power Cable

N777-C Series of Tunable Laser Family

The Keysight N7776C Top-Line Tunable Laser Source

The Keysight N7778C Value Line Tunable Laser Sources

The Keysight N7779C Basic Line Step-Tunable Laser Source

O-band option for Silicon Photonics/ Integrated Photonics Applications

E-band option for CWDM8 Component Testing

N777-C Front and Rear Panel

Input/Output Signals

Optical Output

Polarization Maintaining Fiber

Angled Contact Connectors

LAN Interface

The LAN LED

The LAN Reset button

USB Interface

Powering Up the Instrument

Connecting the Instrument

Connecting over USB

Connecting over LAN

N777-C User Interface

3 Definition of Terms

Definition of Terms

General Definitions

Absolute wavelength accuracy (continuous sweep mode)

Absolute wavelength accuracy (stepped mode)

Dynamic power reproducibility (continuous sweep mode)

Dynamic relative power flatness (continuous sweep mode)

Effective linewidth

Linewidth

Maximum output power

Mode-hop free tunability

Operating temperature and humidity

Output isolation

Polarization extinction ratio

Power flatness versus wavelength

Power linearity

Power repeatability

Power stability

Relative intensity noise (RIN)

Relative wavelength accuracy (continuous sweep mode)

Relative wavelength accuracy (stepped mode)

Return loss

Side-mode suppression ratio

Signal to source spontaneous emission (SSE) ratio

Signal to total source spontaneous emission ratio

Wavelength range