Agilent B User Datasheet

User's Guide

HP

Reectometer

8504B

Precision

HP part number: 08504-90046

Printed in USA March 1995

1400 Fountaingrove Parkway,

Santa Rosa, CA

95403-1799, USA

Notice.

The information contained in this document is subject to change

without notice. Hewlett-Packard makes no warranty of any kind with regard

to this material, including but not limited to, the implied warranties of

of

shall

this

merchantability

for

liable

be

not

damages

in connection

and

errors

tness

contained

with

for

the

a

particular

herein

or

furnishing,

Hewlett-P

purpose

for

.

incidental

performance

ackard

consequential

or

use

or

,

material.

.

.S

U

the

Restricted

Rights

Government

Rights

the

of

252.227-7013

Commercial

agencies

other

Legend.

subject

is

echnical

T

in

DOD

for

Computer

.

Use

restrictions

to

Data

agencies

Software

duplication,

,

as

Computer

and

subparagraphs

and

,

Restricted

set

or

forth

Software

Rights

disclosure

in

clause

by

subparagraph

at

and

FAR

at

(c)

clause

(c) (1)

(1)

(c)

ARS

DF

the

of

(2)

52.227-19

(ii)

for

c



Copyright Hewlett-P

ackard Company 1992, 1993, 1994, 1995

written permission is prohibited, except as allowed under the copyright laws.

WARNING

This is a IEC Class 1 LED product. Do not stare into beam or view

directly with optical instruments. LED radiation is emitted from the

front-panel

TEST PORT

and

REFERENCE EXTENSION A

connectors.

WARNING

ARNING

W

CAUTION

If this instrument is not used as specied, the protection provided by the

equipment could be impaired. This instrument must be used in a normal

condition (in which all means for protection are intact) only.

qualied

operator

No

personnel.

.

covers

Before

switch

installed.

switching

set

is

Assure

Electrostatic

connectors

.

momentarily

touching

void

A

instrument.

the

prevent

buildup of

serviceable

prevent

o

T

on

voltage

the

to

the

discharge

Therefore

the

short

rear-panel

the

sure

Be

static

electrical

this

supply

(ESD)

before

,

center

inside

parts

product,

the

of

voltage

can

connecting

and

connectors

the

that

charge

.

shock

make

power

is

damage

outer

instrument

.

servicing

Refer

LED

and

that

sure

supply

specied

the

in

circuits

cable

any

conductors

without

is

and

properly

to

radiation,

line-voltage

the

correct

the

range

associated

rear-panel

a

to

the

of

touching

rst

earth-grounded

do not

.

with

cable

remove

selector

is

fuse

rear-panel

connector

together

frame

the

.

to

This instrument has been designed and tested in accordance with IEC

Publication 348,

Safety Requirements for Electronic Measuring Apparatus

,

and has been supplied in a safe condition. The instruction documentation

contains information and warnings which must be followed by the user to

ensure safe operation and to maintain the instrument in a safe condition.

,

of

iii

The HP 8504B at a glance

The HP 8504B precision reectometer is a high-resolution interferometer

that measures return loss. It is optimized for single-mode ber, but useful

measurements can also be made in multi-mode ber. The precision

reectometer performs measurements at 1300 nm and 1550 nm wavelengths.

Typical applications include:



Measurements of launch optics for lasers and opto-electronic integrated

circuits.



Measurements

connectors,

High-resolution



known

Measurement



refractive

between

High-resolution



Measurements



crystals

.

of passive

and isolators

measurements of

refractive

of

discontinuities

two

measurement

of

index.

bulk

ber-optic devices

.

lightwave path

material

of

index

.

path

of

devices

optic

length,

such

as

lenses

such as

based

couplers

discontinuities

a

on

expressed

AR

,

known

transit

as

coatings

attenuators

on

based

distance

.

time

,and

,

a

iv

Using the precision reectometer, you can display multiple reections from

the device that you are testing. For example, the following gure shows an

LED device with ve reective surfaces.For each surface, the gure shows

the corresponding response on the precision reectometer's display.

v

Guided procedures

reduce measurement

time

The precision reectometer provides

guided setup

and

guided calibration

procedures that help you prepare the instrument for measurements.

These procedures consist of a series of screens that present step-by-step

instructions.

Procedure Task

changed

be

adapters

Front-panel

can

Softkeys select

instrument features

guided setup

Selects light source and calibrates the instrument for

pigtailed or non-pigtailed devices.

guided calibration

Calibrates the instrument.

You can also manually calibrate the instrument for maximum exibility.

guided

for

Chapter

to

Refer

calibrations

should calibrate

You

the instrument

After



Before



The

with

be

a

in

other

\Front-P

to

available

making

precision

9/125

changed or

easily

counterclockwise direction.

adapters

adapter

2

.

the instrument:

any

reectometer's

ber-optic



m

measurement performance

, but

anel Fiber-Optic

types

complete

a

has warmed

measurements.

three

All

.

cables

cleaning.

removed

for

Useful measurements

Adapters"

.

explaination

1

for

up

front-panel

connectors

three

Simply

Chapter

in

guided

of

.

hour

connectors

unscrew

may

5

not

for

setups

are

be

complete

a

and

compatible

are

adapters

adapter

each

achievable

optimum.

listing

that

with

Refer

can

of

Many instrument features are available through the use of softkeys. Softkeys

are the eight keys that are located along the right-hand side of the display.

The denitions for these keys are shown on the display next to the key and

change for dierent menus.

vi

Annotation

Shown

in

the

Display's

\Status

Notation" Area

Status

Description

Notations

* Measurement parameters changed: measured data is in doubt until a complete clean sweep has been taken.

Avg Sweep-to-sweep averaging is on. The averaging count is shown immediately below this notation.

C Error correction (measurement calibration) is on.

D Dispersion correction is on. This notation is available for the 1550 nm source only.

panel.

rear

the

at

trigger

external

for an

ext W

Hld Hold sweep

OVL Amplitude

aiting

.

of

reected

signal

.

large

is too

port

test

at

vii

front-panel

4

5

G/n

4

5



M/

4

5

K/m

knob

alues

continuous

functions

changed

Allows

various

V

require no

erminates

T

erminates

T

erminates

T

by

terminator

units

numeric

adjustments

start

as

such

knob

the

.

keypad

to

value

eective

are

entries

current

scale

,

with

with 10

and

for

others

values

,

immediately

9

6

10

multiplier

6

10

multiplier

6

3

multiplier

,

.

and

.

4x15

4

ENTRY OFF

viii

Terminates unitless entries such as averaging factors.

5

Disables the keypad, knob, and step keys until another

function is selected.

Keys in this manual

4

5

letters indicate normal front-panel keys. Most of these functions also can be performed using

boxed

softkeys.

NNNNNNNNNNNNNNNNNNNN

shadow

letters indicate softkeys.

ix

CAUTION

Safety Symbols

The following safety symbols are used throughout this manual. Familiarize

yourself with each of the symbols and its meaning before operating this

instrument.

The

caution

sign denotes a hazard to the instrument. It calls attention to a

procedure which, if not correctly performed or adhered to, could result in

damage to or destruction of the instrument. Do not proceed beyond a

caution

sign until the indicated conditions are fully understood and met.

attention to

calls

adhered

a

warning

with

manual.

the

in

It

this symbol

,could

to

sign until

result

when

beyond

and

product

instructions

hazard.

or

met.

marked

is

life-threatening

.

are

Do

the

a

correctly

proceed

not

understood

fully

symbol.

manual

refer

to

user

performed

The

the

to

denotes

warning

G

N

I

N

R

A

W

The

procedure

injury

in

indicated

Instruction

Manual

sign

which,

of

loss

or

conditions

instruction

The

necessary

if

not

life

for

a

the

is

it

L

symbol.

mark

when the

on

o

is

symbol.

registered

a

design was

trademark

proven.)

a

y

accompanied

(If

European

the

of

Community

.

b



line-power

j

CE

The

year

line-power

CE

it is

,

ISM1-A This is a symbol of an Industrial Scientic and Medical Group 1 Class A product.

CSA The CSA mark is a registered trademark of the Canadian Standards Association.

x

Certication and Assistance

Hewlett-Packard Company certies that this product met its published

specications at the time of shipment from the factory.Hewlett-Packard

further certies that its calibration measurements are traceable to the United

States National Institute of Standards and Technology (NIST), to the extent

allowed by the Institute's calibration facility, and to the calibration facilities of

other International Standards Organization members.

Product maintenance agreements and other customer assistance agreements

available

are

any assistance

For

Oce.

Hewlett-P

for

, contact

ackard

your nearest

products.

Hewlett-P

ackard

Sales

and

Service

xi

Warranty

This Hewlett-Packard instrument product is warranted against defects in

material and workmanship for a period of one year from date of shipment.

During the warranty period, Hewlett-Packard Company will, at its option,

either repair or replace products which prove to be defective.

For warranty service or repair, this product must be returned to a service

facility designated by Hewlett-Packard. Buyer shall prepay shipping charges

to Hewlett-Packard and Hewlett-Packard shall pay shipping charges to return

duties

product

the

and taxes

.

Buyer

to

for products

However

,

returned to

Buyer

shall

Hewlett-Packard

pay

shipping

all

from

charges

another

,

country

.

,

Hewlett-Packard

Hewlett-P

instructions

does

rmware

The

or

ackard

when

warrant

not

be

will

foregoing

inadequate

interfacing,

environmental

maintenance

or

NO

OTHER

W

SPECIFICALL

MERCHANT

ABILITY

warrants that

for use

with an

properly installed

the

that

uninterrupted

warranty

maintenance

unauthorized

specications

.

ARRANTY

DISCLAIMS

Y

AND

its software

instrument

operation

error-free

or

not

shall

Buyer

by

modication

for

EXPRESSED

IS

THE

FITNESS

on that

the

of

to

apply

Buyer-supplied

,

or

product,

the

OR

IMPLIED

FOR

and rmware

execute

will

instrument.

instrument,

tion

a

Limit

.

operation

,

improper

or

resulting

defects

misuse

IMPLIED

ARRANTIES

W

ARTICULAR

P

A

designated

programming

its

Hewlett-P

software

or

W

of

software

site

HEWLETT-P

.

OF

PURPOSE.

by

ackard

or

,

arranty

improper

from

or

outside

preparation

A

of

CKARD

Exclusive Remedies

THE REMEDIES PROVIDED HEREIN ARE BUYER'S SOLE AND EXCLUSIVE

REMEDIES. HEWLETT-PACKARD SHALL NOT BE LIABLE FOR ANY

DIRECT,

AMA

D

LEGAL

INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL

ANY

OR

,

TORT

,

GES

THEORY

WHETHER

.

ASED

B

ON CONTRA

CT

OTHER

the

xii

Installing

WA

RN

IN

Installing

This chapter shows you how to install your precision reectometer and how

to verify that it is operating properly. Be sure to save the shipping containers

in the event that the instrument should need to be returned to HP.Itis

important to have the correct packaging.

Refer to Chapter 6 for information on operating conditions such as

temperature.

If you should ever need to clean the cabinet, use a damp cloth only.

continued protection

G

For

same type

correct

The

and ratings

fuse types

against re

use of

. The

are listed

hazard, replace

fuses

other

rear

the

on

or

panel

line

materials

each

of

prohibited.

is

instrument

with

only

fuse

section.

N

I

N

R

A

W

ON

I

T

U

A

C

CAUTION

out

and

(outside

If

, then

for

to

of

the

forced

a

external

an

that

power

a cabinet,

in

the

watts

100

cabinet

via

common

its

supply

.

the

ambient temperature

maximum

dissipated

greater

is

G

If

voltage

neutral

When

product

the

cabinet)

the

product

the

power

total

reduction,

(earthed

installing

product

this

convection

is

pole)

the

not

must

be

must



4

by

C

dissipated

be

must

sure

make

the

of

product

restricted. The

be

than

less

every

for

the

in

used.

energized

be

to

autotransformer

terminal

convection

operating

the

in

800

than

connected

is

into

temperature

cabinet.

watts

This product is designed for use in INSTALLATION CATEGORY II and

POLLUTION DEGREE 2, per IEC 1010 and 664 respectively.

1-2

Installing

Contents

Step 1. Inspect the shipment

Step 2. Connect the two instrument sections

Step 3. Set the line voltage

Step 4. Connect the rear-panel cables

Step 5. Verify Operation

To replace the line fuse

:::::::::::::::::::::::::::::::::::::::::::

::::: ::::::: ::::::: :::::: ::

::::: ::::::: ::::::: :::::: ::::::: ::::::::: ::::

::::::: :::::: ::::::: ::::::: ::::::

:::::: ::::::: :::::: ::::::: ::::::: ::::::::: :::::

:::::: ::::::: :::::: ::::::: ::::::: ::::::::: ::::::

Cleaning Connections for Accurate Measurements

To clean a non-lensed connector

To clean an adapter

To test insertion loss

To test return loss

Instrument

our

return

o

Y

the

Returning

T

instrument

:::::::::::::::::::::::::::::::::::::::::::::::::

::::::::::::::::::::::::::::::::::::::::::::::::

:::::: :::::: ::::::: ::::::: :::::: ::::::::: :::::::::

:

for

::::: ::::::: :::::: ::::::: ::::::: ::::

:

service

:

:::::: ::::::: :::::: ::

:

::

:

1-4

1-6

1-8

1-11

1-12

1-20

1-22

1-24

1-25

1-26

1-27

:

1-28

:

1-3

Step 1. Inspect the shipment



Verify that all system components ordered have arrived by comparing the

shipping forms to the original system purchase order. Inspect all shipping

containers.

If your shipment is damaged or incomplete, save the packing materials

and notify both the shipping carrier and the nearest Hewlett-Packard

sales and service oce. HP will arrange for repair or replacement of

damaged or incomplete shipments without waiting for a settlement from

transportation

the

problems

Notify

company

.

the

customer engineer

HP

of any

1-4

Precision Reectometer Accessories

Item Quantity

Standard:

Wood box 1

100 cm FC/PC ber-optic cable 2

Fiber-optic cable adapter

1

Low-reection termination 1

Isopropyl alcohol cleaner (30 ml) 1

Cotton swabs 1

Tape measure (3 m) 1

cable

001

tra

cm

BNC

IO

Accessory

y

cable

ber-optic

FC/PC

ber-optic

FC/PC

ber-optic

FC/PC

INTERCONNEC

cable

Kit:

1

adapter

cable

ber-optic

cable

ber-optic cable

ber-optic

cable

T

Rear-panel

Rear-panel line-power

Option

Cable

Fiber-optic

40

50

75

125

150

175

Installing

Step 1. Inspect the shipment

1

2

cables.

ber-optic

FC/PC

two

connect

to

Used

1

1-5

Step 2. Connect the two instrument sections

WARNING

Always disconnect and separate the two instrument sections before lifting

or moving the instrument. Otherwise, you may harm yourself or damage

the instrument.

1. Verify that serial number labels on the two instrument sections contain

the same serial number.You'll nd these labels on the precision

reectometer's rear panel. Make sure that the serial number and options

listed on the labels match the serial number and options listed on the

shipping document.

in)

so

.

in

that

front

the

of

the

2. Place

Place

3.

front

lightwave

the lightwave

the display

of the

edge

section.

section on

processor on

a steady

top

display processor

of

is

sturdy

,

the

about

work

lightwave

cm

0.6

surface

section

(0.25

4. Slightly lift the rear of the display processor and slide it back until

edge is even with the front edge of the lightwave section.

1-6

its front

Installing

Step 2. Connect the two instrument sections

Hooks on the top of the lightwave section will slide into slots on the

display processor and lock the front panels of the two sections together.

5. Conrm that the two instruments are locked together by very gently lifting

up on the front of the display processor. If the display processor separates

from the lightwave section, they are not locked together properly.

6. Tighten the rear-panel thumbscrews on the locking feet.

7. Ensure that there is a minimum of seven centimeters (three inches) free

space around the instrument to provide for adequate cooling.

1-7

Step 3. Set the line voltage

CAUTION

Severe damage to the instrument can result if line voltage settings are

incorrect when power is applied.

The line-power

.

Determine

1.

should

voltage

line

the

not

be connected to the precision reectometer at this time.

of

power

C

A

the

source

cords

2. Use a small at-blade screwdriver to set the display processor's

line-voltage selector switch to the value determined in step 1.

3. Use a small at-blade screwdriver to open the display processor's pull-out

fuse

drawer

following

the

See

.

gure.

1-8

Installing

Step 3. Set the line voltage

V

4.

correct.

250V

On

5.

line

beneath

the

erify

,

Notice

holder

the

module

following

that the

The

part

HP

that

.

lightwave

cover

the

value of

the

recommended

extra

2110-0780.

fuse

number

an

section,

.

door

located

is

that

tag

gure

line-voltage

fuse

is provided

a

use

cover

The

along

fuse

both line-switch

for

a

in

at-blade

door

screwdriver

is

cover

the

hinged

the

in

drawer

door's

pull-out

settings

located

to

the

on

right-side

drawer

on

pry

left

a

is

the

open

side.

edge

is

F3.0A,

fuse

the

Pry

.

See

1-9

Installing

Step 3. Set the line voltage

be

must

position,

in

and

voltage

rotate

N

O

I

T

U

A

C

Do

the

line

module

attempt

not

completely

to

or

removed

the

non-repairable

line

the

from

selector

damage

module

cam

will result.

rotated

,

to

The

the

cam

proper

installed

is

it

while

reinstalled.

6. Remove

7. Rotate

the voltage

selector

cam

to

from

the

line

the

desired

module

voltage

.

When

.

the

line

module cover is closed, the selected voltage will be visible through a

small window.

8. Insert the voltage selector cam back into the line module.

9. Verify that the value of the line-voltage fuse in the pull out draw is

correct.

recommended

The

fuse

for

100V

and

120V

operation

F1.5A, 250V

a

is

,

HP part number 2110-0043. The recommended fuse for 220V and 240V

operation is a F0.75A, 250V

10. Close the line-module cover door

, HP part number 2110-0063.

.

1-10

Step 4. Connect the rear-panel cables

WARNING

N

O

I

T

U

A

C

This is a Safety Class 1 Product (provided with a protective earthing

ground incorporated in the power cord). The mains plug shall only be

inserted in a socket outlet provided with a protective earth contact.

Any interruption of the protective conductor inside or outside of the

instrument is likely to make the instrument dangerous. Intentional

interruption is prohibited.

Always use the three-prong AC power cord supplied with this instrument.

Failure

to ensure

instrument damage

I/O

Connect

1.

lightwave

Connect

2.

the

section.

BNC

the

adequate earth

.

interconnect

between

cable

grounding

cable

the

by

between

display

the

processor

the

and

lightwave

cause

may

cord

this

using

not

section.

Connect

3.

the

power

cable

to

display

processor

and

lightwave

the

section.

the

1-11

Step 5. Verify Operation

This step takes approximately 20 minutes to complete.

Equipment Required

The following equipment is supplied with the precision reectometer.



Two 100 cm FC/PC ber-optic cables.



One ber-optic cable coupling adapter.



One low-reection ber-optic termination.

Tighten

connectors

Over-tightening

measurements.

sheet

data

Turn

1.

hour

one

Clean

2.

Refer to

for

the

all

properly

under-tightening

or

nger

ys

Alwa

torque

y

an

precision

connectors

tighten

recommendations.

reectometer

.

cable

connectors

and

\Cleaning Connections

in

result

can

consistent

a

in

and

on,

front-panel

ccurate

A

for

misalignment

manner

it

allow

optical

Measurements"

and

Refer

.

to

ports

warm

nonrepeatable

manufacturer's

the

to

for

up

.

for

information on cleaning connectors.

3. Attach one of the 100 cm ber-optic cables to the front-panel

TEST PORT

connector.

at

least

When mating Super PC connectors, check to see that the keyways on

inserted

PC cable

Super

the

connectors

there is a protective cap on the free end of the ber-optic cable

4. If

.

connectors

are

into

on

slots

the

it.

5. Attach the other 100 cm ber-optic cable between the front-panel

REFERENCE EXTENSION

connectorsAandB.

1-12

mating

the

, remove

Installing

Step 5. Verify Operation

The

REFERENCE EXTENSION

equal in length in order for reections to be viewed on the display.

and

TEST PORT

ber-optic cables must be

6. Press

N

Do not move the reference extension cable for the rest of this procedure

will change the reference signal polarization and will invalidate the calibration.

4

PRESET

The wavelength defaults to 1300 nm.

OTE

5

.

y movement

.An

of this cable

1-13

Installing

Step 5. Verify Operation

7. Press

4

CAL

5

and then

GUIDED CAL

.

8. Use the supplied adapter to connect the low-reection termination to the

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

open end of the

TEST PORT

cable.

Do not connect the termination to the front-panel connector as

suggested on the screen.

Low Reection Termination

9.

djust

A

until

the

two

line

front-panel

the

in

is

REFERENCE

shaded

area.

POLARIZATION

following

the

See

BALANCE

gure

knobs

.

10.

Disconnect

11.

12.

Press

The end of the cable is providing

.

DONE

the low-reection

NNNNNNNNNNNNNNNNNNNNN

NN

FRESNEL

and then

termination

NNNNNNNNNNNNNNNNNNNNN

NNNNNNNNNNNNNNNNNNNNNNNNN

from

MEASURE STANDARD

a Fresnel standard.

the

NNNN

.

ber-optic

cable

.

N

NN

N

Press

13. Wait until the asterisk on the display's left-hand side disappears and the

letterCremains below the asterisk.

1-14

Installing

Step 5. Verify Operation

14. You should see a Fresnel response on the display due to a reection from

the end of the test port cable. If the response is missing, check the

following, and repeat this procedure from the beginning:

Are the the front-panel cables properly connected?

Are the rear-panel cables attached to the correct connectors?

response.

Fresnel

15.

Press

4

MKR FCTN

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

5

,

MAX SEARCH

, and then

NNNNNNNNNNNNNNNNNNNNNNNNNN

MKR ZOOM

.

This expands the display around the Fresnel response.Wait for the

response to move to the center of the display.

NN

N

NN

N

NN

N

16.

N

Press

display

MAX

.

SEARCH

the

If

value

and

,

not within

is

read

the

values

marker's

clean all connectors on the cables and front

procedure

Peak value

Peak value (1550 nm

from step 1.

(1300 nm source)

source)

::::::: :::::: ::::::: ::

:::::: :::::: ::::::: :::::

amplitude

shown

value

below

panel, and repeat this

::::

on the

thoroughly

,

0

15 dB

0

14.7 dB

6

0.5 dB

6

0.5 dB

1-15

Installing

Step 5. Verify Operation

17.

1-16

Connect

coupling

a

Marker showing

adapter to

peak

the

value

end

with

of

the

1300

TEST

nm

source.

PORT

ber-optic

cable

.

Installing

Step 5. Verify Operation

18. Partially insert the connector of another cable into the adapter. Observe

the Fresnel reection of this connector as you insert the cable.

19.

Repeatedly press

adapter

original

the

to

following gure

until

NNNNNNNNNNNNNNNNNNNNNNNNNN

MKR ZOOM

span

the

response

.

as you slowly insert the connector into the

resolved.

be

should

is

as

mm.

1

possible

The Fresnel

can still

and

response

be

See

as

close

the

1-17

Installing

Step 5. Verify Operation

signal.

single

a

as

20.

21.

Press

turn on

the

of

4

MEAS

4

MKR

the delta

peaks

5

F

.

and

CTN

T

then

N

,

5

MAX

marker

responses

wo

N

NN

N

TRIGGER:HOLD

N

NN

N

SEARCH

and

N

to

viewed

N

NN

N

and

,

reference

N

then

to

freeze

N

MARKER

xed

the

NN

N

the

N

NN

N

trace

N

!

marker

N

.

N

NN

N

FIXED

to

N

MKR

zero

N

to

one

on

22. Turn the front-panel knob to center the marker on the other peak.

23. The displayed spatial resolution shown in the marker area should be less

than the following values:

1300 nm source

source

nm

1550

:::::::::::::::::::::::::::::::::::::::::::::

:

::

:

::

:

::

:

0.025 mm

0.25

::

:

mm

1-18

Installing

Step 5. Verify Operation

24.

25.

26.

4

Press

PRESET

4

MENU

Remove

procedure

the

from

.

5

and then

5

coupling

step

Delta

N

1550

adapter

to

7

marker

N

check

N

nm

from

showing

N

NN

N

.

the

spatial

ber-optic

operation

resolution.

cable

1550

at

,and

nm.

repeat this

1-19

To replace the line fuse

T



1.

2.

1-20

o

change

the

Disconnect

small at-blade

Use a

shown

in the

the

on

fuse

line-power

the

screwdriver

following gure

display

cord

processor

from

to

.

the

open

section:

display

pull-out

the

processor

fuse

section.

drawer

as

To replace the line fuse

3. The recommended fuse for both line-switch settings is a F3.0A, 250V,

HP part number 2110-0780.

Notice that an extra fuse is provided in a drawer located on the fuse

holder.



To change the fuse on the lightwave section:

1. Disconnect the line-power cord from the lightwave section.

2. On the lightwave section, use a at-blade screwdriver to pry open the

line-module cover door. The cover door is hinged on the left side. Pry

beneath the tag that is located along the cover door's right-side edge.

.

See

the

following

gure

Installing

the fuse

out

Pull

3.

fuse:

100V and 120V operation

220V and 240V operation

drawer

.

The

:

following

::::::: :::::

:::::: ::::

recommended

list

shows

the

F1.5A 250V (HP p/n 2110-0043)

F0.75A 250V (HP p/n 2110-0063)

1-21

Cleaning Connections for Accurate

Measurements

Accurate and repeatable measurements require clean connections. Use the

following guidelines to achieve the best possible performance when making

measurements on a ber-optic system:



Keep connectors covered when not in use.



Use dry connections whenever possible.



Use the cleaning methods described in this section.

CAUTION

care in



Use



When

sure

or

Because

ensure

gaps

inserting a

that

adapter

of

good

damaged

,

the

.

the

connections

index-matching

connections

dry

Use

connections

Dry

Diamond

40

,

return

dB

(and can

ackard

example

has

improve

Hewlett-P

handling all

ber-optic

ber-optic connector

does

end

ber

cores

of

size

small

oor

P

.

contamination,

,

ends

ber

Dry

be

or

used

better

.

connectors

with

,

compounds

.

can

HMS-10/HP

loss

degrade) performance

strongly

recommends that

connectors

touch

not

in

used

connections

are

physically

FC/PC,

making

,

DIN,

into a

the

a

.

front-panel

outside

optical

result

and

easier

of the

bers

from

improper

clean

to

contacting

ST).

and

connection

wet

index matching

adapter

mating connector

care must

,

misalignment,

core

and

use

to

and

connectors

connection

dry

a

If

probably

will

compounds NOT

make

,

be

removal

keep

(for

used

of

clean.

not

be applied to their instruments and accessories. Some compounds,suchas

gels, may be dicult to remove and can contain damaging particulates.If

you think the use of such compounds is necessary, refer to the compound

manufacturer for information on application and cleaning procedures.

Cleaning

Accessories

Item HP Part Number

Isopropyl alcohol 8500-5344

Cotton swabs 8520-0023

Small foam swabs 9300-1223

Compressed dust remover (non-residue) 8500-5262

to

air

1-22

Inspecting

Cables

Fiber-Optic

Consistent

indication

insertion

the

your

test

you

the

and

future

receipt,

in

Connector

lightwave

as

little

as

another

is

better

the

physically

although

Dust Caps Provided with Lightwave Instruments

measurements

have

you

that

and/or

loss

cables

the

retain

degradation

any

if

insertion)

(or

dB

.

of

connector

0.1

important

larger

(the

contacting

dB

40

to

30

Cleaning Connections for Accurate Measurements

Item HP Part Number

Laser shutter cap 08145-64521

FC/PC dust cap 08154-44102

Biconic dust cap 08154-44105

DIN dust cap 5040-9364

HMS10/HP dust cap 5040-9361

ST dust cap 5040-9366

lightwave

your

with

connections

good

of

is

values

It

.

return

common.

loss

for

data

occurred.

has

important

one

are

performance

a measure

is

, the

loss

have

return

accessories

and

measured

loss

Typical

with high

loss

factor

the

connectors

more

is

However

.

lightwave

your

insertion

comparison,

for

than

less

of

smaller the

return

equipment

you

,

cables

and

loss

you

performance

of

dB

1

connectors

reection:

reection).

better

losses

good

a

are

wish

may

accessories

or

be

loss

able

return

will

characteristic

and

,

loss

Return

.

reection

less

the

The

than 50

Installing

to know

.If

upon

tell

to

of

sometimes

loss

best

dB,

a

You can visually inspect your cables

Although it is not necessary, visual inspection of ber ends can be helpful. Contamination or

imperfections on the cable end face can be detected as well as cracks or chips in the ber itself. Use

a microscope (100X to 200X magnication) to inspect the entire end face for contamination, raised

metal,

Visible

keep

dents

or

imperfections

bers

the

in the

from

as

metal

touching

not

contacting).

well

the

as

ber

imperfections.

other

y

an

not

y

ma

core

Inspect

performance (unless

aect

imperfections

the

chips.

and

cracks

ber for

the

1-23

Installing

Cleaning Connections for Accurate Measurements

To clean a non-lensed connector

CAUTION

Do not use any type of foam swab to clean optical ber ends.Foam swabs

can leave lmy deposits on ber ends that can degrade performance.

1. Apply isopropyl alcohol to a clean lint-free cotton swab or lens paper.

Cotton swabs can be used as long as no cotton bers remain on the ber

end after cleaning.

2. Before cleaning the ber end, clean the ferrules and other parts of the

connector

Apply

3.

Clean

4.

paper

Some

remove

them.

.

isopropyl

ber

the

and

back

amount

particles

This

alcohol

with

end

across

forth

wiping

of

when

technique

new

a

to

swab

the

mild

or

application

remove

can

clean lint-free

lens paper

or

several

end

ber

scrubbing

alcohol

of

displace

or

cotton swab

.Move

times.

ber

the

of

alone

particles

the

will

swab

end

not

smaller

or lens

or

help

can

remove

than

paper.

lens

micron.

Immediately

5.

lens

6. Blow

ltered, dry

ber

the

.

paper

across the

, compressed

end face

ber

the

dry

connector end

.

end

air.

a

with

face from

Aim the

clean,

dry

distance

a

compressed

lint-free

,

gas

of

6

at

cotton

to

a

swab

inches

8

shallow

using

angle

Nitrogen gas or compressed dust remover can also be used.

one

or

to

CAUTION

Do not shake,tip, or invert compressed air canisters, because this releases

particles in the can into the air. Refer to instructions provided on the

compressed

soon

As

7.

air

as

canister

the

.

connector

cover it

connect

,

dry

is

or

for

.

use

later

1-24

Cleaning Connections for Accurate Measurements

To clean an adapter

1. Apply isopropyl alcohol to a clean foam swab.

Cotton swabs can be used as long as no cotton bers remain after

cleaning. The foam swabs listed in this section's introduction are small

enough to t into adapters.

Although foam swabs can leave lmy deposits, these deposits are very

thin, and the risk of other contamination buildup on the inside of

adapters greatly outweighs the risk of contamination by foam swabs.

.

swab

adapter

foam

with

clean,

a

dry

foam

,

swab

.

2. Clean

3. Dry

the adapter

the inside

with the

of the

Installing

be

air.

used.

this

on

releases

the

, compressed

ltered,

compressed

the

.

using

.

air

dust

Refer

adapter

,

the

air

the

or

gas

or

,

tip

can

canister

compressed

invert

into

through

Blow

4.

Nitrogen

N

O

I

T

U

A

C

Do

particles

in

shake

not

compressed

dry

also

remover

air

to

can

because

canisters

,

instructions provided

To test insertion loss

Use an appropriate lightwave source and a compatible lightwave receiver to

test insertion loss. Examples of test equipment congurations include the

following equipment:

Option

71451A

71450A

HP



built-in



HP 8702 or HP 8703 lightwave component analyzer system



HP 83420 lightwave test set with an HP 8510 network analyzer



HP 8153 lightwave multimeter with a source and power sensor module

or HP

white

light

source.

optical

spectrum

analyzers

with

002

1-25

Installing

Cleaning Connections for Accurate Measurements

To test return loss

Use an appropriate lightwave source, alightwave receiver, and lightwave

coupler to test return loss. Examples of test equipment congurations include

the following equipment:



HP 8703 lightwave component analyzer



HP 8702 analyzer with the appropriate source, receiver, and lightwave

coupler



HP 8504 precision reectometer

8153 lightwave



HP

conjunction with

81554SM

HP



multimeter with

a lightwave

source

dual

and

coupler

81534A

HP

source

a

power

and

return loss

sensor

module

in

1-26

Returning Your Instrument

It is unlikely that your precision reectometer should need to be returned

to the Hewlett Packard. However, if you do need to return it, repackage

the instrument using the original shipping containers and materials or their

equivalents. Hewlett-Packard oces can provide packaging materials identical

to the original materials.

CAUTION

Packaging materials not specied can result in instrument damage. Never

use styrene pellets to package electronic instruments. The pellets do not

adequately

and can

generate static

cushion

instrument,

the

electricity.

do

not

prevent

instrument

all

movement,

1-27

Installing

Returning Your Instrument

To return the instrument for service

1. Fill out the repair form (located on the next page), and place it in the box

with the instrument. Send a copy of any noted error messages or other

helpful performance data.

2. To help prevent damage during transit, pack the instrument in the

factory packaging materials. Although the original shipping materials

or equivalents are best; the following instructions result in acceptable

packaging:

reduce

rap the

a. W

ESD damage

instruments

or

F

b.

double-walled,

strength.

accommodate

of

sides

Surround

c.

protect

to

packing

Sealed

from

plastic

Cap.

Air

provide

instrument in

.

weigh

that

corrugated

The

instrument

the

foam

Air

sheeting

Wrapping

carton

the

equipment

module

is

must

instrument.

for

and

available

not

Corporation,

with

lled

the instrument

sucient protection

anti-static

less

cardboard

both

be

Allow

packing

three

with

prevent

to

the

,

Hayward,

1-1/4

and also

plastic

than

best

inch

to

(120 lb),

54 kg

carton

large

at

of

enough

least

material.

inches

four

to

movement

alternative

California

bubbles

air

several

times

prevent movement

3. Seal the carton with strong nylon adhesive tape.

4. Mark the carton FRAGILE, HANDLE WITH CARE.

5. Retain copies of all shipping papers.

159

three

.

the

kg

and

to

of

the

in

is

94545.

Use

this

in

possibility

a

use

(350

strong

four

packing

carton.

.-240

.D

S

pink

material

in

lb) test

enough to

inches

material

If

Air

Cap

Air

anti-static

carton.

the

of

on all

TM

Cap

is

should

1-28

Date:

Company:

Address:

Technical contact person:

Phone:

number:

Model

number:

Serial

number:

.

.O

P

Accessories

returned

with

Other:

unit:

Service Repair Form

cables(s)



none



power

Returning Your Instrument

adapter(s)



cable

Installing

Service

Other:

Failure

If

Needed:

symptoms

is

unit

part

and

of

special

system,

control

list model



number(s)

calibration

settings:

only

of

other

repair



interconnected

repair



instruments:

and

calibration

1-29

Installing

Returning Your Instrument

Hewlett-Packard Sales and Service Oces

U.S. FIELD OPERATIONS

Headquarters

Hewlett-Packard Company

19320 Pruneridge Avenue

Cupertino, CA 95014 U.S.A.

(800) 752-0900

Colorado

Hewlett-Packard Company

24 Inverness Place, East

Englewood, CO 80112

649-5000

(303)

Jersey

New

y

Compan

ackard

Hewlett-P

Road

Century

est

W

120

07653

NJ

aramus,

P

586-5400

(201)

Headquarters

S.A.

ackard

Hewlett-P

vril

Nant-d'A

Me

yrin

du

2/Geneva

150, Route

1217

Switzerland

780.8111

22)

(41

Britain

Great

Hewlett-Packard Ltd.

Eskdale Road, Winnersh Triangle

Wokingham, Berkshire RG11 5DZ

California, Northern

Hewlett-Packard Company

301 East Evelyn

Mountain View, CA 94041

(415) 694-2000

Georgia

Hewlett-Packard Company

2000 South Park Place

Atlanta, GA 30339

955-1500

(404)

exas

T

Compan

ackard

Hewlett-P

Road

Campbell

East

930

75081

Richardson,

(214)

EUROPEAN

TX

231-6101

FIELD

OPERA

France

ackard

Hewlett-P

Canada

Du

venue

1A

Courtaboeuf

De

D'Activite

Zone

Cedex

Ulis

es

L

F-91947

France

60

82

69

1)

(33

y

TIONS

California, Southern

Hewlett-Packard Company

1421 South Manhatten Ave.

Fullerton, CA 92631

(714) 999-6700

Illinois

Hewlett-Packard Company

5201 Tollview Drive

Rolling Meadows, IL 60008

342-2000

(708)

Germany

GmbH

ackard

Hewlett-P

Bad

y

Strasse

Homburg

16-0

Hewlett-Packard

61352

German

6172)

(+49

1-30

Hewlett-Packard Sales and Service Oces (continued)

INTERCON FIELD OPERATIONS

Installing

Headquarters

Hewlett-Packard Company

3495 Deer Creek Rd.

Palo Alto, California 94304-1316

(415) 857-5027

China

China Hewlett-Packard Company

Road

Huan X1

Bei San

38

Shu

u

Y

Shuang

District

Hai Dian

China

Beijing,

256-6888

1)

(86

aiwan

T

aiwan

T

ackard

Hewlett-P

Building

H-P

Floor,

8th

Road

North

Hsing

Fu

337

aiwan

T

aipei,

T

712-0404

2)

(886

Australia

Hewlett-Packard Australia Ltd.

31-41 Joseph Street

Blackburn, Victoria 3130

(61 3) 895-2895

Japan

Yokogawa-Hewlett-Packard Ltd.

, Sagamihara

Yabe

1-27-15

Japan

Kanagawa

(81 427)

229,

59-1311

Canada

Hewlett-Packard Ltd.

17500 South Service Road

Trans-Canada Highway

Kirkland, Quebec H9J 2X8

Canada

(514) 697-4232

Singapore

Hewlett-Packard Singapore Ltd.

. Ltd.

Pte

87

Box

.

.O

Alexandra

P

singapore 9115

271-9444

(65)

1-31

Installing

2

erforming

P

Guided

and Calibrations

Setups

Performing Guided Setups and Calibra-

tions

This chapter shows you how to perform a

calibrations

, and manual calibrations. Calibrating the precision reectometer

guided setups,aguided

consists of balancing the receiver and then calibrating the magnitude. These

two procedures ensure maximum accuracy for your measurements. They

remove DC osets and polarization sensitivity. They also set a calibrated

reference level.

Guided setups not only calibrate the instrument, but they also select the

display

source

and

Manually calibrating

instructions

the instrument

both

for

is generally

pigtailed

non-pigtailed

and

faster that

using

devices

the

.

guided

calibration.

When the instrument is calibrated, the status indicator

appears on the display's left-hand side.

2-2

C

Performing Guided Setups and Calibrations

Contents

hardware

Some

required

Running Guided Setups and Calibrations

To perform a guided setup (devices with pigtail)

To perform a guided setup (devices without pigtail)

To perform a guided calibration

Performing Manual Calibrations

To balance the receiver

To calibrate the magnitude

::::: ::::::: :::::: ::::::: ::::::: ::::::::

:::::: ::::::: ::::::: :::::: ::::::: ::::::::: :::

::::::::::::::::::::::::::::::::::::::::::

To calibrate for an external source

To turn o calibration data

:::::: :::::: ::::::: ::::::: :::::: ::::::::: :

To enter the standard's reection percentage

To turn chromatic dispersion correction on and o

tray

cable

successful

for

001

calibration, clean

Accurate

Measurements"

, supplied

Option

the

use

o

T

E

T

O

N

a

ensure

to

order

In

need

Connections

following hardware

the

\Cleaning

to

ou'll

is

Y

:::::: ::::::: ::::::: :::::: ::::::

:::::: :::::: ::::::: ::

:::::: ::::::: ::::

:::::: ::::::: ::::::: :::::: ::::::: ::::

:::::: :::::: ::::::: ::::::: :::::: ::

:::::: ::::::: ::::::: :::

:::::: ::::::: :::::

:

calibration.

the

to

1in

HP

prior

this

8504B

chapter

,

.

calibrate

to

all ber-optic

Chapter

in

connectors

with

:

the

2-6

2-7

2-13

2-18

2-20

2-23

2-25

2-26

2-28

2-29

Refer

instrument:

matched-length cables

set of

A



A low-reection termination.

.

You can use any termination that has a return loss that is greater than

30 dB.

2-3

Performing Guided Setups and Calibrations

Matched-length cables

ensure response is

visible

During calibrations and subsequent measurements, two cables must be

connected to the precision reectometer. One cable connects the device

being measured to the front-panel

front-panel

EXTENSION

PORT

The relative lengths of these two cables determine the position of the Fresnel

reection (from the end of the

REFERENCE EXTENSION

may not be visible on the screen. This is shown in the following gure.

REFERENCE EXTENSION A

cable must be equal in length (or slightly shorter) than the

cable.

cable is too long or too short, the measured response

TEST PORT

andBconnectors. The

TEST PORT

. The other cable connects the

REFERENCE

TEST

cable) on the screen. If the

2-4

lengths determine response position.

Cable

Performing Guided Setups and Calibrations

Changing the span does

not aect calibrations

Any calibration performed in less than full span is still valid after the start or

stop values are changed. Likewise, a calibration performed in full span is still

valid after the start or stop values are changed.

Keep the reference cable stationary

Do not move the reference-extension cable connected between

B

on the front during or after a calibration. Moving this cable changes the polarization and voids

REFERENCE EXTENSION A

and

the calibration. If you have an Option 001 accessory kit, use the kit's cable tray to help keep the

reference extension cable stationary.

to

Unlike the

reference-extension cable

cable bending.

balance

the

eep

K

move

not

Do

compromises

knobs

the

Therefore,

knobs

either

of

this

stationary

front

the

calibration.

the

,

y

ma

cable

reference-polarization

panel

test-port

moved

be

cable

without

unaected

is

degrading

balance

y

b

the

knobs

changes

calibration.

after

polarization

in

calibration.

due

Moving

2-5

Running Guided Setups and Calibrations

This section shows you how to perform

guided setups

for pigtailed or

nonpigtailed devices. (A pigtail is a length of ber-optic cable which usually

terminates in a connector.) Guided setups can be started using either the

4

PRESET

5or4

SYSTEM

5

keys. Using the

4

PRESET

5

key has the advantage of

setting the instrument to a known state.

During a

guided calibration

, a polar vector display shows polarization

balance between two receivers in the instrument. After manually adjusting

precision

the

,

polarization

the

balance

using

reectometer mathematically

between the

complete

calibrate

specied

the

for

TEST PORT

calibration, a

magnitude.

standard

the

cable and

The displayed

in

front-panel

the

compensates for

the

REFERENCE

standard cable

percentage

knobs

any polarization

known

of

response

reectance

of

EXTENSION

reectance

scaled

is

.

to

match

imbalance

T

.

paths

used

is

the

o

to

value

2-6

To perform a guided setup

(devices with pigtail)

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Select

cables

1.

Press

4

PRESET

5

and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

GUIDED SETUP

2. Press a softkey to select the wavelength.

3.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

CLASSIFY DEVICE

and then

NNNNNNNNNNNNNNNNNNNNNNN

PIGTAIL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

4.

Measure

5.

additional

connector

Based

6.

chart

CONNECT

the

cable

.

the

on

assemble

to

CABLES

length of

used

length

.

the device's

connect

to

measured

ber-optic

a

pigtail. Include

the device

preceding

the

in

for

cable

.

the

.

front-panel

to the

step

reference

the length

the

use

,

path.

any

of

PORT

TEST

following

2-7

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Cable Lengths

Length of Path

for Tested Device

engths

L

1

Standard

2

Connect

7.

REFERENCE

If

with the

1

40 | 65 40

50 | 75 50

75 | 100 75

90 | 115 40 + 50

100 | 125 100

115 | 140 40 + 75

125 | 150 125

140 | 165 40 + 100

175

|

150

190

|

165

200

|

175

215

|

190

225

|

200

240

|

215

centimeters.

in

are

from

cables

length

cables

the

EXTENSION

an

have

you

cable tray

Assemble this

150

+

40

175

+

40

+

50

+

40

001

Option

assembled

Option

.Coil

2

Cable

125

150

175

L

kit.

accessory

in

connectors

accessory

001

cable

the

engths

the

A

Length of Path

for Tested Device

1

225 | 250 50 + 175

240 | 265 40 + 50 + 150

250 | 275 75 + 175

265 | 290 40 + 50 + 175

275 | 300 100 + 175

290 | 315 40 + 75 + 175

300 | 325 175 + 125

315 | 340 40 + 100 + 175

350

|

325

365

|

340

375

|

350

390

|

365

400

|

375

centimeters.

in

are

between

B

.

you

step

can

necessary

as

stabilize

preceding

and

kit,

around

150

40

75

40

50

If

.

using more than one cable, place the mid-connectors in the wide part

of the slot. Let the ends of the cable protrude from the tray.Besure

to place the cover on the tray.

Assemble this

+

Cable

175

125

100

150

2

175

+

175

+

175

+

175

+

front-panel

cable

the

are

you

Check

setup

8. Connect your device to the front-panel

9.

Press

N

NN

N

CHECK

N

NN

N

SETUP

NN

N

.

10. W

2-8

TEST PORT

complete.

.

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Connect termination

NN

N

BALANCE

press

.

number

N

and

,

steps:

N

NN

DONE

follow

following

perform

,

visible

not

4

CAL

the

one

for

4

G

V

A

the

for

the

4

SYSTEM

screen.

N

NN

N

the

N

NN

is

NN

N

,

5

CALIBRATE

prompts

sweep

full

then

and

5

instrument

side

left

and

5

NN

N

TERMINATION

device from

N

NN

N

NN

N

NN

on the

N

AVERAGING

the

of

then

N

Low

N

NN

N

NN

N

MENU

complete

to

N

to

graticule

N

GUIDED

N

the

Reection

N

.

response

a

If

11.

a.

Press

b.

ollow

F

Wait

c.

d.

Press

ait

W

e.

On

f.

Press

the

N

Press

12.

13.

14. Connect the low-reection termination directly to the

15. Press

CONNECT

Disconnect

N

BALANCE RECEIVER

the

N

NN

screen. Then

N

average

N

NN

.

TEST

and

,

N

NN

N

NN

N

then

.

N

.

ON

16

the

,

N

SETUP

PORT

Termination

sweeps

Avg

N

.

N

RECEIVER

N

.

will

the

TEST PORT

N

NN

count

prompts

N

.

16.

to

on

.

2-9

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Balance Receiver

16. Adjust the two polarization balance knobs until the line is in the shaded

area.

N

NN

N

Press

17.

E

T

O

N

DONE

.

After

degrades

2-10

balancing

measurement

the

receiver

accurac

extension

the

move

not

do

,

.

y

cable

balance knobs.

the

or

,

Movement

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Calibrate Magnitude

Under

Connect

T

Device

est

18. Disconnect the termination from the

19. Connect a second cable that is the same length as the

EXTENSION

cable to the

TEST PORT

.

REFERENCE

The free end of this cable serves as the \Fresnel" cal standard. When

using the supplied cables, the free end of the cable functions as the

calibration standard. This is possible because the percentage of light

reected by that type of cable connector is known. (For 1300 nm

measurements, the correct value is 3.16%; for 1550 nm, 3.37%.) Other

calibration standards (cables, connectors, or devices) may have other

reection values.

press

20.

are

you

If

NN

N

FRESNEL

NN

using

If

.

you

cables

are

from

using

Option

the

another

001

standard,

accessory

perform

kit,

the

steps:

dB).

(in

N

STD

for

PORT

NN

N

.

N

TEST

N

NN

loss

softkey

standard

the

.

PORT

N

SETUP

.

N

to

.

complete

be measured.

to

a.

b.

21.

Press

Disconnect

22.

Connect

23.

Press

24.

setup

Obtain

Enter

N

MEASURE

N

MEASURE

and begin

N

NN

the

NN

N

the

this

N

NN

standard's

using

value

N

NN

N

STANDARD

from

cable

the

be

N

device

N

to

N

NN

N

DEVICE

device measurements

reection

N

the

USER

N

and

,

TEST

the

tested

then

and

N

to

return

NN

N

wait

the

N

EXIT

NN

following

guided

the

25. As you measure devices

, observe the following suggestions:

2-11

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations



Use the

4

START

5

and

4

STOP

5,4

CENTER

5

and

4

5

, and marker keys to

SPAN

optimize the displayed response.

Reducing the span increases measurement speed, improve

resolution, and increase dynamic range.



To improve the signal-to-noise ratio, use averaging. Turn on averaging

by pressing

4

AVG

5

and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

AVERAGING on OFF

so that

highlighted.

NNNNNNNN

ON

is

2-12

To perform a guided setup

(devices without pigtail)

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Select

Check

cables

setup

1.

Press

4

PRESET

5

and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

GUIDED SETUP

2. Press a softkey to select the wavelength.

3.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

CLASSIFY DEVICE

and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

NO PIGTAIL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

4.

5.

6.

CONNECT

Locate

Connect

connectors

you

If

with

using

the

of

place

to

7. Connect

8. Connect

N

Press

9.

CHECK

CABLES

ber-optic cables

two

the

of

one

and

A

an

have

tray

cable

the

than

more

Let

slot.

cover

the

second

the

device

your

N

NN

N

SETUP

B

Option

N

.

that are

cables between

.

accessory

001

the

Coil

.

place

,

cable

one

the

of

ends

the

tray

the

on

ber-optic

TEST

the

to

N

NN

N

,

and

wait

front-panel

cable

.

cable

PORT

one

for

of equal

around

the

to

complete.

.

length.

REFERENCE

can

you

kit,

necessary

as

mid-connectors

protrude

the

cable

full

from

front-panel

.

measurement

stabilize

.

in

the

TEST

sweep

EXTENSION

cable

the

are

you

If

wide

the

Be

.

tray

.

PORT

to

part

sure

2-13

Connect

termination

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

10. If a response is not visible, perform the following steps:

N

a.

Press

4

b.

Follow the prompts on the screen. Then press

c. Wait for one full sweep to complete.

d.

Press

4

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

5

,

CALIBRATE MENU

CAL

5

and then

AVG

, and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

AVERAGING ON

N

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

BALANCE RECEIVER

NNNNNNNNNNNNNN

DONE

.

e. Wait for the instrument to average 16 sweeps.

On the left side of the graticule,the

f.

Press

4

SYSTEM

5

and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

GUIDED SETUP

Avg

number will count to 16.

, and follow the prompts on

the screen.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

11.

Disconnect

12.

Use

13.

TEST

CONNECT

supplied

the

PORT

TERMINATION

device

the

adapter

.

cable

from

.

TEST

the

connect the

to

cable

PORT

low reection

.

termination

.

the

to

Balance

Receiver

14.

15. A

2-14

Press

djust the

area.

N

NN

N

BALANCE

two polarization

N

NN

N

RECEIVER

N

Low

N

.

balance

Reection

ermination

T

knobs

until

the

line

shaded

the

in

is

16.

Press

N

DONE

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

N

.

T

O

N

balancing

After

degrades

E

measurement

the

receiver

accurac

the extension

move

not

do

,

.

y

cable or

Movement

knobs.

balance

the

2-15

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

Calibrate Magnitude

Connect

T

Device Under

est

17. Disconnect the termination and adapter from the

TEST PORT

cable.

Fresnel calibration standard

The free end of the

TEST PORT

cable serves as the \Fresnel" calibration standard. When using

the supplied cables, the free end of the cable functions as the calibration standard. This is possible

because the percentage of light reected by that type of cable connector is known. (For 1300 nm

measurements, the correct value is 3.16%; for 1550 nm, 3.37%.) Other calibration standards (cables,

connectors, or devices) may have other reection values.

NN

N

press

,

the

reection

the

N

NN

N

,

tested

N

and

cables

following

N

USER

wait

and

to

then

return

N

NN

N

the

N

EXIT

N

STD

N

for

TEST

N

FRESNEL

steps:

loss

softkey

standard

the

PORT

NN

N

SETUP

N

(in

N

dB).

.

cable

N

to

are

If you

.

measured.

be

to

.

complete the

using

guided

18. If

another

a.

b.

19.

Press

Connect the

20.

Press

21.

you are

Obtain

Enter

N

MEASURE

N

MEASURE

using

standard,

standard's

the

value

this

N

NN

N

device

NN

N

supplied

the

perform

using

N

STANDARD

be

to

N

NN

DEVICE

setup and begin device measurements.

2-16

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

22. As you measure devices, observe the following suggestions:



Use the

4

START

5

and

4

STOP

5,4

CENTER

5

and

4

5

, and marker keys to

SPAN

optimize the displayed response.

Reducing the span increases measurement speed, improve

resolution, and increase dynamic range.



To improve the signal-to-noise ratio, use averaging. Turn on averaging

by pressing

4

AVG

5

and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

AVERAGING on OFF

so that

highlighted.

NNNNNNNN

ON

is

2-17

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

To perform a guided calibration

1. Press

2.

3.

Press

4

PRESET

5

NNNNNNNNNNNNNNNNNNNNNNN

1300 nm

4

5

and then

CAL

.

or

NNNNNNNNNNNNNNNNNNNNNNN

1550 nm

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

GUIDED CAL

to select the source wavelength.

.

4. Locate two ber-optic cables that are of equal length.

5. Connect one of the cables between front-panel

.

B

and

plan

A

measure

to

guided

a

measure

to

device

a

setup

device

a

that

(devices

that

has

with

does

connectors

you

If

6.

o

\T

you

If

7.

perform

REFERENCE EXTENSION

have

continue

in

a

pigtail,

a

pigtail)"

not

following steps:

front-panel

the

to

perform

o

cable

guided

a

setup

a. Connect

b. Continue

pigtail)" in

the

at

second

step

this

ber-optic

in

13

chapter

\T

.

chapter

this

pigtail,

TEST

(devices

at step

the

do

PORT

without

13 in

.

2-18

Performing Guided Setups and Calibrations

Running Guided Setups and Calibrations

2-19

Performing Manual Calibrations

The precision reectometer allows you to control many of the aspects of

calibrations.For example, you can change the reection percentage (return

loss) used during magnitude calibrations for the standard. You can also

prevent the application of calibration data to the measured data.

A full calibration consists of two procedures:



Balance internal receiver.



Magnitude calibration.

guided

these

and

procedures

separately

Both of

these procedures

calibrations.

This section

are included

shows you

in guided

how to

setups

run

.

Calibrating

devices

Calibration

provided

are

pigtailed

standards

guided

the

shown

As

steps

the

has

termination

end

the

is

magnitude

A

reection

in

used

pigtail,

a

of a

same length

at

to

during

connected directly

is

cable

calibration

end

the

measured response

value is

displayed.

setup

calibrated

balance

the

During

.

the

as

consists

the

of

to match

procedure

devices

receiver

to

magnitude

the

pigtail

is

of

PORT

TEST

the amplitude

there

,

or

with

calibration

TEST

the

calibration,

connected

measuring

cable

are

without

PORT

the

to

\standard"

a

The

.

the

of

dierences

slight

pigtails

the

.

low-reection

connector

ber-optic

a

PORT

TEST

instrument

\standard"

If

instead

of

then

so

between

device

the

cable

connector

known

scales

the

that

of

at

that

.

the

true

The ber-optic cables supplied with the precision reectometer can be used as

calibration standards. This is because the cable's open end is a very accurate

and repeatable calibration standard. (The insertion loss at the front panel

connection is not taken into account.)

The

return

loss

the ber

of

end

of

these

cables

known

is

to

following

the

have

values:

nm

1300

1550 nm

:

::

:

::

:

::::::::::::::::::::

:

::

:

:::::: :::::: ::::::: ::

(3.16%

dB

15

:

::

:

14.7 dB (3.37% reection)

reection)

2-20

Performing Guided Setups and Calibrations

Performing Manual Calibrations

The values listed above are derived from the following formulas:

Ensuring accuracy of

low-level reections

015dB

014:7dB

=10

Log0:

0316

0337

You can direct the precision reectometer to use your own calibration-

standard values during a magnitude calibration. Using your own optical

device of known reectance for a standard can improve dynamic accuracy.

When observing reections at low levels, perform the balance receiver

calibration periodically after a full calibration to ensure better accuracy.

Periodically balancing the receiver helps to remove small \drifts" when

the

when

often

incoming

block

a

arms

operation

two

most

at

for

into

light

diagram

interferometer

the

of

polarizations.

least

of

the

two

the

receiver

The

hour

one

orthogonal

instrument.) A

generates

and

reference

the

,

receiver

balance

prior

displaying

instrument

.

use

to

olarization

P

receiver

The

polarizations.

photodiode

the interference

arm reections

calibration ensures

very small

allowed to

is not

balance

a

contains

to

(Refer

optical

the

mixes

in

signal

to

needs

that

signals.

calibration:

polarization

Diagram

\Block

elds

polarization.

each

about

be

condition

this

This drifting

occurs

temperature stabilize

story

inside

the

y

an

splits

that

splitter

for

5

Chapter

in

"

two

the

reected

equally

from

proper

ensure

o

T

between

split

met.

is

the

During balance

receiver calibration,

the

TEST

PORT

cable

terminated

is

with

reection

low

a

termination. This means substantially that the only light that hits both receiver detector diodes is from

the mirror in the reference light path. The polarization of this light is then adjusted by the front panel

reference polarization balance knobs such that the responses from each detector are equal, or balanced.

Subsequent measurements of polarization-independent return loss are then insensitive to polarization

transformations of the ber in the test arm.

2-21

Performing Guided Setups and Calibrations

Performing Manual Calibrations

Reduce the eects of

chromatic dispersion at

1550 nm

External

sources

can

used

You can turn o the use of chromatic dispersion correction data. This allows

you to use your own correction methods.

When making measurements at 1550 nm, the amount of chromatic dispersion

experienced by the light traveling in the reference path will be less than

that in the path of the device being tested. This is due to that fact that, in

most cases, light traveling in the path with the device being tested is all in

ber. However, part of the reference path is in an open beam (inside the HP

8504B). This mismatch in dispersion results in a broadening and subsequent

drop in the peak value of the displayed reection \impulse".

The peak value decreases monotonically as a function of the length of the

corrected

been

has

dispersion

the

of 17

order

open

subsequent

In

be

external

convenience

a

the

kHz

features

an

use

mismatch.

precision

reectometer

ps/(nm)(km). The

dB.

6

0.3

of

beam,

the eects

uncertainties

addition

to the

source

for users

are

an

user.)

When

not

source

external

typical

signal.

external

with

eect

This

The

.

result of

the

to

path

the

If

are very

due to

internal

1300

for measurements

very

with

The

using

applied

to

"

source

external

an

to

learn

source

external

measurement

the

how

.

consistent

is

instrument

this correction

device

dicult

chromatic dispersion

and

nm

(The

.

advanced

must

source

calibrate the

to

and

assumes

being

remove

to

nm

1550

external

applications

be

normal

,

data.

dispersion

a

leaves

tested

sources

source

able

residual

a

both

is

the

from

approach

can

you

,

input

It

.

modulated

be

to

calibration

to

Refer

error

in

measurement;

can

provided

is

not

is

and correction

calibrate for

\To

precision reectometer

coecient

ber

5

use

meant

out

on

and

dB

an

with

.

for

by

the

as

a

an

27

2-22

Performing Guided Setups and Calibrations

Performing Manual Calibrations

To balance the receiver

1. Turn the precision reectometer on, and allow it to warm up for at least

one hour.

2. Locate two ber-optic cables that are of equal length.

If you plan to measure a device that has a pigtail, the cables must be

equal to (or up to 240 mm shorter than) the length of the pigtail.

3. Connect one of the cables between front-panel

.

and

connectors

you plan

4. If

low-reection termination

.

cable

plan

you

If

5.

termination

E

T

O

N

reference

the

move

not

Do

reference

the

change

will

B

A

to measure

measure

to

directly

to

extension

signal

device

a

to

device

a

TEST

the

cable

polarization

that

TEST

that

the

for

and

PORT

rest

will

does

using

a pigtail,

has

.

this

of

invalidate

not

procedure

the

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

6. Press

7.

8.

4

5

and then

CAL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

BALANCE RECEIVER

two

Adjust

the

CALIBRATE MENU

polarization

.

balance

.

knobs

until

area.

REFERENCE EXTENSION

have

the

pigtail,

a

remaining

connect

y

An

.

connect

ber-optic

low-reection

a

movement

this

of

calibration.

the shaded

in

is

line

the

a

cable

2-23

Performing Guided Setups and Calibrations

Performing Manual Calibrations

N

Press

9.

DONE

.

10.

Remove

low-reection

the

termination.

2-24

Performing Guided Setups and Calibrations

Performing Manual Calibrations

To calibrate the magnitude

Always balance the receiver before calibrating the magnitude. Balancing the

receiver ensures that the displayed response magnitude is insensitive to the

polarization transformations of the ber in the test arm when the return loss

of the device being tested is polarization-independent.

1. Calibrate the reference balance as described in \To balance the receiver".

2. If you plan to measure a device that has a pigtail, connect a ber-optic

cable to the

TEST PORT

.

is the

cable

to

return

.

3.

4.

5.

This cable

the

REFERENCE

4

Press

CAL

N

Press

CALIBRATE

a

Select

Press



Press

(in

loss

The

percentage of

must be

and

5

N

NN

N

standard:

N

NN

N

FRESNEL

N

NN

USER

dB)

sweep

EXTENSION

then

N

STD

your

of

can

equal to

N

NN

N

CALIBRATE

N

NN

N

MAGNITUDE

the

select

to

N

your own

use

to

standard.

any

at

be

reectance

length

the

connectors

N

NN

N

MENU

N

.

standard

position.

the

of

cable

the

of

.

N

.

default

value

standard. Enter

Fresnel

The

of

end

open

the

value

ber-optic

the

that

.

attached

is

reection

listed

6. Wait until the asterisk on the display's left-hand side disappears and the

letterCremains below the asterisk.

You should see a Fresnel response on the display due to a reection

from the end of the

TEST PORT

cable.

2-25

Performing Guided Setups and Calibrations

Performing Manual Calibrations

To calibrate for an external source

1. On the lightwave section's rear panel, locate the cover plate that is just

left of the

I.O. INTERCONNECT

cable.

2. Turn the two thumbscrews to remove the cover plate.

3. Disconnect the green ber-optic cable, and put a protective cap on it.

4. Turn the external source o.

5. Connect a ber-optic cable from your external source to the

INPUT

6. Turn

one

Locate

7.

Connect

8.

connector

the precision

.

hour

two

plan

you

If

to

equal

one

connectors

plan

you

If

9.

low-reection

.

cable

plan to

If you

10.

termination directly to the

.

ber-optic

measure

to

up

(or

the

of

.

B

and

A

measure

to

termination

measure a

reectometer on,

are

a

mm

between

device

a

to

device

that

device

shorter

TEST

that

cables

240

cables

TEST PORT

allow

and

equal length.

of

a

has

the

than)

front-panel

not

does

using

PORT

pigtail,

a

has

.

warm

to

it

pigtail, the

length of

REFERENCE

pigtail,

a

have

remaining

the

connect

NOTE

movement

Any

Do

will

not move

change

the

reference

extension

signal

cable

polarization

for

and

the

will

of

rest

invalidate

procedure

this

the calibration.

.

SOURCE ARM

for

up

cables

the

must

pigtail.

EXTENSION

connect

ber-optic

low-reection

a

of

at

this

least

be

a

cable

11. Press

2-26

4

MENU

5

and then

NNNNNNNNNNNNNNNNNNNNN

NNNNN

EXTERNAL

.

Performing Guided Setups and Calibrations

Performing Manual Calibrations

CAUTION

12.

13.

Press

4

5

and then

CAL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

BALANCE RECEIVER

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

CALIBRATE MENU

.

The power of the external source should not exceed 5 mW.Power levels

greater than 5 mW can damage the HP 8504B.

14. Turn the external source on. Intensity modulate the external source at

27 kHz.

Without the modulation, the displayed response contains a high noise

level.

15.

djust

A

the

polarization

two

balance

knobs

shaded

the

in

is

line

the

until

area.

16. Press

Remove

17.

Continue

18.

NNNNNNNNNNNNNN

DONE

the

with

.

low-reection

of

2

step

termination.

o calibrate

\T

magnitude

the

section.

this

in

"

2-27

Performing Guided Setups and Calibrations

Performing Manual Calibrations

To turn o calibration data

This procedure does not destroy the calibration data. It only prevents its

application to the measurement data. Turning the calibration on, restores the

previous calibration.

1. Press

2.

o

T

1.

2.

3.

4.

4

5

.

CAL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

Press

CORRECTION on OFF

standard's

enter

Press

the

4

.

5

CAL

N

NN

N

CALIBRATE

N

NN

N

USER

STD

N

during magnitude

return to

To

the

N

NN

N

MENU

N

,

and

enter

calibrations

default

N

.

value

NNNNNNNNNN

so that

N

OFF

reection

the

your

for

N

press

,

FRESNEL

is selected.

return

standard.

N

percentage

dB)

(in

loss

NN

N

.

to

be

used

To turn chromatic dispersion correction on and o

1.

2.

3.

2-28

Press

4

.

5

CAL

N

NN

N

Press

CALIBRATE

NNNNNNNNNNNNNNNNNNNNNNNNN

NNNNNNN

Press

DISPER COR on OFF

N

NN

N

NN

N

MENU

.

NNNNNNNNNNNNNNNNNNNNN

so that

NNNNNNN

OFF

NNNN

is selected.

Performing Guided Setups and Calibrations

Performing Manual Calibrations

To use the Option 001 cable tray

The maximum length of cable that can be coiled inside the tray is

approximately 200 cm (79 inches).

CAUTION

1. Connect one end of the ber-optic cable to the front panel

EXTENSION B

connector.

REFERENCE

2. Coil the cable in the tracy as shown in the following gure. Do not allow

any more cable outside the cable tray than is necessary.

If the cable must be lengthened inside the tray by using two cables and

an adapter

cable tray

Connect

3.

REFERENCE

optic

Fiber

diameters

stretching

Attach

4.

.

the

EXTENSION

cable

than

less

cable

the

the top

the connectors

, put

remaining

be

can

mm

50

.

the

onto

the

of

end

connector

A

irrepairably

inches).

(2

body

main

adapter

and

ber-optic

.

damaged

damage

This

the

of

cable to

by

cable

foam

the

in

bending

mainly caused

is

.

tray

cutout

the front-panel

into circles

it

inside

with

by

the

2-29

Performing Guided Setups and Calibrations

Performing Manual Calibrations

2-30

3

erforming

P

Measurements

Contents

Performing Measurements

Once you've calibrated the precision reectometer, you're ready to make

measurements. In this chapter, you'll learn about changing the measurement

range, temporarily storing traces, and changing the colors on the display.

You'll also learn how to use displayed markers and how to test the shape

of displayed responses using limit lines. Limit lines are valuable tools for

pass/fail testing on production lines.

The last section of this chapter shows you how to create hard copies of the

screen,

the

plotter

printer

a

display

the precision

points and

on

reectometer can

instrument parameters

Setting

Reducing

Using

Creating

Storing Traces to Memory

the Measurement

select the

o

T

automatically

o

T

change

o

T

change

o

T

Displayed

reduce

o

T

Markers

display

o

T

To change the measurement range

To make relative measurements

To position a xed reference marker

To change the peak denition

To turn markers o

Limit

enter

o

T

To display or hide limit lines

To turn on limit testing

Tutorial: Using Limit Lines

To view memory traces

or

source

displayed

the

refractive

the

displayed

the

:

peak

a

Lines

limit-line

Range

wavelength

to

tune

Noise

:

response

::::: ::::::: :::::: ::::::: ::::::: ::::::::: ::::::::

:

segments

addition

In

.

print or

.

:

response

a

:

scale

:

index

::

:

::

:

noise

::

:

::::::: ::::::: :::::: ::::::: ::::::: :::

::::: ::::::: ::::::: :::::: ::::::: :::::::

:

::

:

:::::: :::

::::::: :::::

::::::

::::::: :

:::::::::::::::::::::::::

::::: ::::::: ::::::: ::::::

:

::

:

hardcopies

of

:

::

:

all

::

:

::

:

::

:

getting

to

listing

plot a

:

::

:

::

:

::

:

::

:

::

:

:::::: ::::::: :::::: ::::::: ::::::: :

::::::::::::::::::::::::::::::::

:

::

:

::

:

:::::: :::::: ::::::: ::::::

:::::::::::::::::::::::::

of

measurement

:

::

:

::

:

::

:

::

:

::

:

::

:

::

:

::

:

::::::

::::::::

::::::::::

::::::::::::

::::::: :::::

:

::

:

::

:

3-4

:

3-6

:

3-7

:

3-7

:

3-8

:

3-9

:

3-11

:

3-12

:

3-16

::

3-16

3-17

3-18

3-19

:

3-23

:

3-23

3-24

3-25

3-34

3-35

3-2

Performing Measurements

Performing Manual Calibrations

Contents (continued)

Saving Instrument States to Registers

To save to a register

To recall a register

To increase user memory

Saving Instrument States to Files

To save to a disk

To change a le name

To recall an external le

To delete an external le

To format an external disk

To connect a disk drive

Changing

adjust

o

T

turn on

To

turn o

o

T

Printing

print the

o

T

plot

o

T

print

o

T

enter

o

T

abort

o

T

Colors

and

the

and

displayed

the warning

the \done"

Plotting

display

plot

or

printer/plotter

the

print

a

:::::: ::::::: ::::::: :::::: ::::::: ::::::::: ::::::

::::: ::::::: ::::::: :::::: ::::::: ::::::::: :::::::::

:::::::::::::::::::::::::::::::::::::::::::

:::::: ::::::: ::::::: :::::: ::::::: :::::

:::::: ::::::: :::::: ::::::: ::::::: ::::::::: ::::::::::

::::: ::::::: :::::: ::::::: ::::::: ::::::::: ::::::

:::::: :::::: ::::::: ::::::: :::::: ::::::::: :::

:::::: ::::::: :::::: ::::::: ::::::: ::::::::: :

::::::: ::::::: :::::: ::::::: ::::::: ::::::::

:::::::::::::::::::::::::::::::::::::::::::::

arnings

::

:

beep

:

beep

:

W

:

type

:

::

:

and

:

udible

A

colors

:

measurement

plot

or

::::: ::::::: :::::: ::::::: ::::::: ::

:

::

:

::

:

::

:

::

:

::

:

::

:

::

:

parameter

address

and

:

values

:

::

:

::

:

3-36

3-38

3-39

3-40

3-41

3-42

3-43

3-44

3-45

:

3-45

::

3-45

:

3-46

:

3-47

:

3-48

::

:

3-48

:

3-49

:

3-49

:

3-50

:

3-3

Setting the Measurement Range

It's easy to set the precision reectometer's measurement span. Simply

select the appropriate setting using the

and

4

5

keys. Then, use the front-panel knob, step keys, or numeric key

SPAN

4

START

5

and

4

STOP

5

keys or

4

CENTER

pad to enter the value. Annotation that is displayed on the sceen shows

measurement settings such as source wavelength, vertical and horizontal

scales, reference level, and refractive index.

You can zoom to responses swiftly using automated search and scale

makes

span

functions

.

sweep speed

you

As

faster and

the

use

increases the

instrument,

reducing

notice

that

measurement sensitivity

the

.

5

3-4

Performing Measurements

Setting the Measurement Range

Horizontal scale

readings depend upon

refractive index

The precision reectometer's maximum measurement span depends upon the

refractive index of the light path. The default horizontal scale corresponds to

a refractive index (n) of 1. (This is the value for light in air, and it gives the

precision reectometer's maximum range of 400 mm.) Entering a dierent

refractive index, using the

horizontal scale

Refraction

precision

The

REFERENCE

appears

400

a

cable

approximately

mm

or

F

.)

but

index

reectometer

EXTENSION

(This

span.

28

every

not the position of responses on the display.

=

millimeters

REFERENCE EXTENSION

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

REFRACTIVE INDEX (n)

1.

designed

is

PORT

TEST

and

the

division

one

response

to

reected

is

that

the

that

so

cables

right

TEST

if

are

from

PORT

softkey, changes the

Refraction

the

of

the end

index

lengths

equal,

display's left

the

of the

cable is

1.44.

=

the

of

response

rst

edge in

TEST PORT

longer than

cable, this response moves one division towards the

the

right. Twenty-eight millimeters of actual ber length has an equivalent air

length of 40 mm.

Return

press

the

with

span

full

to

key

a

of

ou

Y

pressing

N

NN

N

return

can

4

MENU

N

NN

N

NN

N

ZERO SPAN on OFF

the

N

5

FULL

N

NN

N

instrument to

NN

N

SPAN

N

NN

N

softkey. This

into what is essentially a programmable delay line

the

N

the

to

N

FULL

N

NN

N

SPAN

N

NN

N

you'll

,

key

nd

the

softkey make the precision reectometer

. It sets the center setting

by

time

any

at

span

nm

400

full

to the former start value and stops the sweep (mirror movement).

3-5

Performing Measurements

Setting the Measurement Range

The sweep can be

stopped

External sources can be

used

Normally, the precision reectometer sweeps the measurement range

continually. Single sweeps are available by pressing

4

MEAS

NNNNNNNNNNNNNNNNNNN

N

5

SINGLE

.Each

time this softkey is pressed, one sweep is taken and then the sweep stops.

You also can force any sweep to restart at the beginning regardless of the

current sweep position. This is especially valuable in wide measurement

spans where sweeps take a few seconds to complete.To restart a sweep,

press

4

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

5

MEAS

MEASURE RESTART

.

In addition to the internal 1300 nm and 1550 nm sources, you can connect an

external source for the measurements. The external source input is provided

meant

not

is

It

normal

data.

how

.

calibration

Refer

calibrate

to

\T

and

o

the

convenience

a

as

typical

the

for

correction

calibrate

precision

select

To

Press

1.

2.

Press

The

users

for

When

.

user

features

for an

are

external source

reectometer for

source

the

4

N

.

5

MENU

NN

N

nm

1300

N

NNNNNNNNNNNNNNNNNNNNNNNNN

EXTERNAL

N

NN

N

or

1550

selection turns o the internal sources. The external

with

using

applied

not

"

use with

wavelength

NN

N

nm

very

an

in

N

to

advanced

external

the

to

Chapter

external

an

select

applications

,

source

measurement

learn

to

2

source

wavelength.

the

source input is provided as a convenience for users with very advanced

applications. Note that normal calibration and correction features are

not available with an external source . Use the entry keys to enter the

wavelength

of

the

external

source.

3-6

To automatically tune to a response

Performing Measurements

Setting the Measurement Range

1. Press

2.

Press

4

MKR FCTN

5

.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

MAX SEARCH

.

3. If the marker is not on the desired response, use the front-panel knob to

place the marker on the response.

NNNNNNNNNNNNNNNNNNNNNNNNN

Press

N

MKR ZOOM

as needed to center the response and reduce the

4.

measurement span.

5.

T

1.

2.

o

4

Press

SCALE

change the

4

Press

F

the

Select

N

NN

N



DISTANCE

N

NN

N



TIME

ORMA

horizontal

N

REF

5

T

N

5

.

and then

displayed

N

AUTO

scale

measurement

SCALE

units:

.

N

NN

N

NN

3. Select the vertical scale:

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN



VERT: LOG MAG

NNNNNNNNNNNNNNNNNNNNNNN



LIN MAG

selects a linear scale.

selects a logarithmic scale.

4.

5.

SCALE REF

N

NN

N

Press

REFERENCE VALUE

.

5

N

NN

N

NN

N

NN

N

, and enter the value at the reference position

4

Press

line.

The reference position line's default position is at the center of the

screen.

6. Press

NNNNNNNNNNNNNNNNNNN

SCALE (/DIV)

NNNNNNNNNNNNNNNNNNN

, and enter the desired units per vertical division.

3-7

Performing Measurements

Setting the Measurement Range

To change the refractive index

1. Press

2.

4

5

MEAS

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

REFRACTIVE INDEX (n)

to 200.

The default value is 1.

.

and enter a refractive index value from 1

3-8

Reducing Displayed Noise

The precision reectometer can average the data from several traces.

Averaging reduces displayed noise especially when used with narrow spans.

For best accuracy, use averaging on the minimum span:

on.

The

default

veraging

A

number

o.

of

trace

averages

is

Source Minimum

1300nm1

mm

16.

Span

veraging

A

1)

=

(n

1550 nm 1.2 mm

In wide spans, the precision reectometer captures more data points than it

can display; adjacent data points are grouped and then the maximum point

points

displayed.

is

group

each

for

decreases

group

per

Since, in wide spans

until

,the

As

displayed.

all

the

points

are

maximum value is averaged, there is a dierence

decreased,

is

span

the

between the averaged value and the true value of

the number

a signal. The dierence (or

of

inaccuracy) increases with noise or span.

3-9

Performing Measurements

Reducing Displayed Noise

The following equation shows the algorithm:

Sn

An=

Kn+01

where:

An= current average

Sn= current measurement

Kn=nforn<F or F for nF

F = averaging factor

1

(

0

K

n

A

n01

)

3-10

To reduce the displayed noise

Performing Measurements

Reducing Displayed Noise

1. Press

2.

3.

4.

4

5

.

AVG

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

AVERAGING FACTOR

average.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

AVERAGING on OFF

You can restart averaging at any time by pressing

, and enter the number of traces you want to

so that

NNNNNNNN

ON

is highlighted.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

AVERAGING RESTART

.

3-11

Using Markers

Markers allow you to read the amplitude values at any position on the trace.

You can easily determine the distance and amplitude value of any response.

The active marker is shown on the display as arsymbol. Inactive markers

are shown with the 1 symbol. The following gure shows markers 1 through

4. Marker 3 is active; markers 1, 2, and 4 are inactive. Notice that marker

4 is a delta marker. Delta markers measure the dierence between two

positions on the display.

3-12

markers

1

relative

display

values

Performing Measurements

Using Markers

Markers are accessed from two front-panel keys:



Use

4

5

to display up to four markers, an additional xed marker,and

MRK

delta markers.



Use

4

MKR FCTN

measurement span based on marker positions.

The active marker can be moved to any point on the trace. When a

logarithmic amplitude scale is used, response values are displayed in dB;

when a linear amplitude scale is used, values are shown as the ratio of

reected power to the incident power. The displayed marker values are valid

even when the measured data is above or below the range displayed on the

screen.

displaying

When

designated

be

relative

delta

than

delta

distance

reference

inactive

the

character

5

to search for peak responses and to change the

markers

four

the

of

any

delta

the

as

(or

displayed

is

marker

appears

markers

reference

time)

next to

,

marker

amplitude

and

a

as

triangles

the

small

.)

marker

The

.

1

one

If

displayed

this

from

character

the

of

number

markers

reference

(This

.

markers

the

on

xed

a

or

show

marker

character

the

is

trace

point

the

The

.

smaller

is

reference

.

can

,

the

a

is

marker

xed

The

marker

delta

special

reference

What if a memory trace

is displayed?

dene a

can

ou

Y

peak

.

trace

the

set

NN

xed

a

on

N

FIXED

N

on

screen;

the

N

NN

N

peak to

MKR

current

the

to

N

. Other

marker

be

a

andb, shown

a

it

N

VALUE

active

markers can

.

identied.

must

trace

not

is

N

NN

N

a

3-13

standard

four

the

of

Each

marker

xed

the

However

limited

position

marker

then

If both data and memory are displayed, the marker values apply to the data

trace. If memory only is displayed, the marker values apply to the memory

trace.

ou

Y

The

increase and then decrease

oors, in order to be dened as a peak.

If peak excursion is dened as 20 dB

in the following gure

,

to

the

position,

activated

be

change

can

default

the

trace

xed

value

.

marker

by

and

the

is

markers

can

N

Use

FIXED

. The

pressing

values

their

amplitude

The

.

dB

6

, relative to the surrounding responses or noise

, must be at least 20 dB in order to be considered

can

position

be

N

NN

N

MKR

xed marker

N

NN

MARKER

referenced

variation

value

N

POSITION

NN

N

FIXED

!

required

species

, then the values of

N

can

N

to

the

N

and

be

NN

N

MARKER

the

for

amount that

anywhere

N

NN

N

positioned

be

only

to

Performing Measurements

Using Markers

peak. Valuesaandbrepresent the respective amplitudes of both sides of a

maximum response. The allowable excursion values range from 0 to 100 dB.

You can also set the level below which nothing will be considered a peak.

This is the peak threshold value. The maximum amplitude of the response

must be at least this value to be called a peak. The allowable threshold

.

dB

75

is

values

3-14

range

from

0

100

to

default

The

.

dB

0

value

0

Performing Measurements

Using Markers

Any part of a peak (as dened by peak excursion) that is less than the

peak threshold value is also used to satisfy the peak excursion criteria. For

example, when the peak excursion is set to 8 dB, a peak that is 4 dB above

and 4 dB below the peak threshold will be considered a peak.

3-15

Performing Measurements

Using Markers

To display a peak response

1. Press

2.

3. If the marker is not on the desired response, front-panel knob or

4.

o

T

1.

2.

3.

4

MKR FCTN

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

MAX SEARCH

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

PEAK SEARCH

NNNNNNNNNNNNNNNNNNNNNNNNNN

Press

MKR ZOOM

measurement

change

Press

the

Use

position.

the

Use

position.

the

4

CTN

F

MKR

front-panel

Press

front-panel

Press

5

.

menus to place the marker.

as needed to center the response and reduce the

span.

measurement

.

5

position

to

knob

N

MARKER

knob

NN

N

MARKER

N

NN

N

NN

N

1

to

N

1

N

START

position

N

STOP

N

NN

N

NN

range

marker

the

N

NN

at

desired

the

.

marker

the

NN

at

desired

the

.

start

stop

make

o

T

Press

1.

osition marker

2. P

relative

4

5

MKR

then

and

1 at the reference position from which relative

measurements will be make

NNNNNNNNNNNNNNNNNNNN

3. Press

4.

Press

1 MENU

NNNNNNNNN

1REF=MKR 1

.

NNNNNNNNNNNNNNNNNNNNNNN

3-16

measurements

N

MARKER

.

1

N

NN

N

NN

N

.

and then .

Performing Measurements

Using Markers

5.

To position a xed reference marker

1.

2.

3.

4.

NNNNNNNNNNNNNNNNNNNNNNNNNN

Press

MARKER 2

Press

4

5

MKR

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

1REF= FIXED MKR

NN

N

Press

FIXED

osition the

P

N

FIXED

ou

Y

N

MARKER

softkeys.

NN

N

NN

N

can

NN

N

MKR

N

also

N

!

to read delta values (marker 20marker 1).

and then

N

NN

MKR

marker using

N

VALUE

N

FIXED

NNNNNNNNNNNNNNNNNNNN

1MENU

N

NN

N

MENU

N

NN

.

specify the

N

NN

N

MKR

.

N

FIXED

position

N

or

.

NN

N

MKR POSITION

value

4

F

MKR

N

CTN

N

5

N

using

N

NN

N

the

NN

N

MARKER

N

and

4

5

MKR

N

!

N

FIXED

N

NN

N

MKR

o change

T

1.

Press

4

MKR FCTN

N

2.

3.

4.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

DEFINE PEAK

value

the

Enter

NN

N

Press

PEAK

considered a peak.

peak

the

5

and then

that

N

NN

N

THRESHOLD

and then

denes

N

NN

N

denition

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

PEAK SEARCH

N

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

PEAK EXCURSION

peak.

a

the

enter

and

.

value

.

below

which

nothing

will

be

3-17

Performing Measurements

Using Markers

To turn markers o

1. Press

2.

Press

4

5

.

MKR

NNNNNNNNNNNNNNNNNNNNNNN

all OFF

.

3-18

Creating Limit Lines

Limit lines allow you to test the shape of displayed responses. Limit testing

compares the measured data with the dened limits, and provides pass or

fail information for each measured data point. Because limit lines allow you

to perform repetitive testing of response shapes, they are ideal for pass/fail

testing on production lines. The tutorial at the end of this section provides an

excellent method of learning about limit lines. It takes only a few minutes to

complete.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Limit

4

Press

SYSTEM

consist

lines

.

tables

following

Each

gure

then

and

5

segments which

of

are

at

has

0

200

segment

LIMIT

upper

an

dB

to

MENU

are entered

lower

and

are

so

and

access

in tabular

limit.

the

o

limit-line

form in

The

displayed

functions

lower limits

scale.

.

limit-line

in the

3-19

Entering

easy

limit

lines

Performing Measurements

Creating Limit Lines

If limit lines are turned on:



They are displayed.



They are included on plots and prints.



In tabular format, upper limit, lower limit, and pass/fail margins are listed

(space permitting).



Limit lines are saved in instrument states.

If limit testing is turned on:



PASSorFAIL

portions

ailing

F



is

or

F

upper

delta

specied

as

each

3

and

limits

.

dB

segment,

lower

instead

dB

0

at

is displayed (even if the limit lines are not displayed).

.

the

of

you must

limit,

upper

of

dB

3

6

trace

and

Enter

.

are

enter a

segment

the

and

the

displayed

starting

lower

middle

type

limits

value

dierent

a

in

position

Alternately

.

example

or

F

.

0

as

color

(distance

you

,

,a

dB and

time),

or

can enter

device may

delta

the

an

limits

Y

value

Up to

pressing

and

22 limit-line

N

MARKER

segments

values

these

enter

can

ou

precision reectometer

segments;

table

you

to

pointer character

,a

a segment,

edit

need

through

scroll

3-20

the

using

N

NN

N

!

can

NN

N

POSITION

be

N

automatically sorts

longer

a

>

shows

select it

which segment

rst using

key

N

added

table

pad

N

,

N

or

the

to

them.

use

the

by

or

N

MARKER

table

The

the

is

NN

N

SEGMENT

setting

N

NN

!

any

in

table

NN

N

SEGMENT

selected

N

NN

the

NN

N

MIDDLE

order

shows

N

NN

softkey

for

N

softkey

marker at

N

.

The

.

up

.

editing.

.

to

In

the

three

the

If

Performing Measurements

Creating Limit Lines

There

segment

are

three

types

are

There

line

Limit

Sloping

segment

three

tables

Lines

to

(SL)

(line

the

types

hold

can

are

or point).

far right

segments:

of

up

drawn

of the

limit-line

The

segments

22

to

ramps

as

Unless terminated

screen.

sloping

from

table.

line

.

the

line

at

,

single

and

,

segment

segment, they

point.

to

the

Flat Lines (FL) are drawn as steps from the horizontal position (but not

vertical location) of the previous segment. Unless terminated by another

segment, they continue to the far right of the screen.

Single Points (SP) are drawn as carets (^or_) at the indicated position when

drawn.

not

stand-alone

When

.

used

terminate

to

a

line

segment,

the caret

is

3-21

Performing Measurements

Creating Limit Lines

Indications of pass/fail

conditions

be

can

lines

Limit

shifted

Several indications of pass or fail status are provided when limit testing is on:

A

PASSorFAIL



The trace vector leading to any measured point that is out of limits is

message is displayed at the right of the display.

displayed in a dierent color. It appears normal on a print or plot.



The limit fail beeper sounds if it is turned on.



An asterisk * is shown next to any listed point that is out of limits.



A bit is set in the HP-IB status byte.

E

T

O

N

a

of

number

changing

move

to

of

can

checked

be

Limits are

device

measurement

can

lines

Limit

to

limits

the

specications

lines away

limit

the

detail.

trace

at

only

specication

of

out

points.

oset

be

correspond

dier in

that

from the

actual

the

without displa

horizontally

with a

stimulus or

measured

data

ying

or

change in

data trace

the

If

points.

sure

Be

.

FAIL

This

test

.

setup

It can

vertically

the

amplitude.

temporarily for

point

to

density

specify

useful

is

or

,

also

visual

insucient,

is

suitable

a

for

device

for

used

be

examination

NOTE

The three

N

NN

N

POSITION

limit

the

3-22

NN

N

oset

N

segments

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

(

ys

ke

AMPLITUDE OFFSET

N

NN

N

NN

N

OFFSET

look out

)

shift

of

the

place

check

,

limit

N

,

MARKER

segments but

the

if

see

to

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

AMP.OFF.

!

values

limit

the

change

not

do

position

y

have

been shifted

in

,

and

in

or

table

the

amplitude

If

.