Agilent 71450B Users Guide

User's Guide

EDF

Noise

A

Gain

Prole Personality for

HP 71450B/1B/2B

HP Part No. 70952-90006

Edition 1

Printed in USA June 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

ackard

this

of

of

shall

material,

this

to

merchantability

be liable

not

damages

for

connection

in

including

tness

and

contained

errors

with

but

for

the

limited

not

particular

a

herein

furnishing,

the

,

to

purpose

incidental

for

or

performance

implied

Hewlett-P

.

warranties

consequential

or

use

or

,

material.

Restricted

Rights

Government

Rights

the

of

252.227-7013

Commercial

agencies

other

Regulatory

71450B/1B/2B

HP

Legend.

subject

is

T

in

for

Computer

to

echnical

agencies

DOD

Software

.

Information.

Optical

duplication,

,

Use

restrictions

and Computer

Data

and

,

Restricted

specications

The

Spectrum

disclosure

or

forth

set

as

Software

subparagraphs

Rights

characteristics

and

eference

Analyzers

R

in

clause

by

subparagraph

at

and

FAR

at

(c)

clause

(c) (1)

contains

(1)

(c)

ARS

DF

of

(2)

52.227-19

chapter

regulatory

(ii)

the

of

for

the

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the

information.

c



Copyright Hewlett-P

ackard Company 1995

All Rights Reserved. Reproduction, adaptation, or translation without prior

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

EDFA Analysis with the EDFA Noise Gain

Prole Personality

The EDFA Noise Gain Prole Personality characterizes erbium-doped ber

ampliers (EDFAs) for signal gain, noise gain, noise gure, and noise gain

peak. The personality uses the time domain extinction (TDE) measurement

technique. The measurement technique used takes advantage of the fact

that, immediately after turning o the input signal, an EDFA's amplied

spontaneous emissions (ASE) has a slow recovery to the undriven state.

Because of its measurement speed, the EDFA Noise Gain Prole Personality is

.

ideal

for

use

manufacturing

in

production

lines

Measurement results

are displayed

graphically

The following

paragraphs describe

three of

the measurements

performed

by

the personality:

erm

T

signal

noise

noise

gain

gain

gain

peak

Denition

provided

Gain

driving

signal

a

of

Gain

driving

is

wavelength

on

describes

certain

a

Indicates

reaches

its

by

the

small

amplier

the

is

the

how

.

range

wavelength

the

maximum

the

amplier

signal

called

noise

amplier

A

EDF

into

as

(such

saturation.

into

noise

the

depends

gain

where

amplitude

to

saturation.

while

noise)

gain

on

noise

the

.

large

the

large signal

a

dependence

Its

prole

wavelength

gain

(trac)

which

over

prole

These essential measurements are often used to match optical ampliers in

long-haul telecommunication systems.

As shown in the following gure, the personality graphically displays swept

measurement results. The top trace shows gain versus wavelength; the

bottom

trace

shows noise

gure

versus

wavelength.

iii

Gain

and

noise

gure

measurement

results.

Required

equipment

personality

The

used

tunable

for

on

available

is

be

also

70953A upgrade

HP

personality requires

The

HP 8168A/B/C



The

included

is

71450B/1B

HP

71450A/1A

HP

installed.

kit

the

Tunable Laser

laser's

modulation

the

with

Option

optical

following

(Option

71452B

HP

optical

053

spectrum

equipment:

003

output

provided

and

spectrum

analyzers

recommended).

triggers measurements

as

analyzers

have

that

sweeps on the optical spectrum analyzer. Another laser can be used

provided it can be modulated at 25 kHz and has an external trigger

output signal that is TTL compatible.



An HP 83424A Option H37 or C25 edge-emmitting LED (EELED).

externally

be

can

C25

or

Because

TTL

a

by

manual

HP

the

compatible

mode

test

83424A

signal,

available

is

Option

H37

ASE

However

from

recommended

the

is

it

EELED

an

using

for

model.

(or

EDFA) that cannot be externally modulated. Option H37's output is

available through a connector



A 3 dB coupler to couple the outputs from the laser and noise source

. Option C25's has a pigtail output.

together.

iv

option

an

can

It

.

had

and

modulated

,a

another

on

the

If not already installed, install the program as described in Chapter 1.

Once installed, you can start the program by pressing

NNNNNNNNNNNNNNNNNNNNNNN

EDFA_NG

softkey.

4

USER

5

and then the

Ensuring the greatest

accuracy

To ensure the greatest possible accuracy, observe the following:



Maintain a resolution bandwidth0.5 nm for best amplitude accuracy.



Perform a user calibration of the optical spectrum analyzer as described in

Chapter 2.



Optical isolator reduces reections.

erbium-doped

Inserting

ber

performance

Clean



ber-optic

Clean

1.

Optical

isolators at

amplier reduces

.

connections

cables

the

are required

do the

,

connectors

Spectrum

the input

the eect

following steps:

described

as

Analyzers

and output

of external

for best

in

User's

Guide

of the

reections on

accuracy

Chapter

Dry

.

When

.

the

of

1

connections

amplier

connecting

71450B/1B/2B

HP

are

recommended.

outside

the

touch

not

does

end

ber

the

that

connectors

Align

2.

mating

After

3.

hand

Refer to

connector

ferrule

the

keep

to

the

Overtightening or

and nonrepeatable



Fusion splices reduce measurement uncertainty.

so

not

Do

.

properly

is

straight

it

and

manufacturer's

undertightening

connections

ber

the

rub

seated

nger-tighten

sheet

data

connectors

.

end

inside

for

against

connector

the

with

it

torque

other

any

use

,

other

the

recommendations

in

result

can

surfaces

one

hand.

misalignment

of the

.

.

The largest source of measurement uncertainty in EDFA measurements

is repeatability of ber-optic connections. Fusion splices reduce typical

connector uncertainties

of

6

0.25

dB

to

uncertainty

splice

dB

0.05

6

a

.

v

Control program using

softkeys or

programming

commands

The EDFA Noise Gain Prole Personality can be controlled either via softkey

menus or remote programming commands. Softkeys are the seven buttons

located on each side of the screen. The functions of softkeys change

according to the menus displayed on the screen. Generally, left-side softkeys

access major menus. Refer to Chapter 3 for a denition of the programming

commands.

Use the following three front-panel keys on the HP 70004A display to select

the available softkey menus:



Press

4

5

to view EDFA Noise Gain Prole Personality menus.The

USER

personality must rst be installed as described in Chapter 1.

.



Press

4

MENU

optical

view

to

5

spectrum

analyzer

menus

Conventions

ey

K



Press

following key

The

4

ront-panel

F

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

N

N

Softkey

Screen

4

DISPLA

N

N

N

N

N

N

Text

.

the

in

menus.

this

labels

right

indicates

guide:

key

a

softkey

a

and

,

or

physically

the

side

left

text

(The

.

softkey

of

displayed

located

softkeys

spectrum

the

labels

on

on

are

the

view HP

5

to

Y

conventions

shown

ext

T

5

ey

k

spectrum

the

shown

ext

T

located

the

are

analyzer

printed

ext

T

instrument's

70004A display

are

this

like

analyzer

this

like

the

to

next

annotation

in

.)

this

display

screen.

used

represents

represents

softkey

on

typeface

vi

Hewlett-Packard Software ProductLicense

Agreement

Important

Please carefully read this License Agreement before opening the media envelope or operating the

equipment. Rights in the software are oered only on the condition that the Customer agrees to

all terms and conditions of the License Agreement. Opening the media envelope or operating the

equipment indicates your acceptance of these terms and conditions. If you do not agree to the License

Agreement, you may return the unopened package for a full refund.

Use

Copies

Adaptations

and

to

the

following:

the

.

the

for

for

a

archival

return

In

Customer

Customer



Customer



Customer may



when

payment

license

may

may

copying

the

of

software

the

in

software

the

use

reverse

not

make copies

adaptation

or

,

purposes

applicable

assemble

adaptations

or

or

,

on

is

until

one

or

essential

an

fee

Hewlett-P

,

terminated,

spectrum

decompile

the

of

step

ackard

subject

analyzer

software

the

software:

the

in

grants

instrument.

use of

software with a computer so long as the copies and adaptations are used

in no other manner.



Customer has no other rights to copy unless they acquire an appropriate

license to reproduce which is available from Hewlett-Packard for some

software

Customer



provided by

.

agrees

that

Hewlett-P

warranty

no

ackard

for

,

any

installation,

free

copies

adaptations

or

or

free

training

made

by

Customer.



All copies and adaptations of the software must bear the copyright

notices(s) contained in or on the original.

is

vii

Ownership

ransfer

T

Software

of

Rights



Customer agrees that they do not have any title or ownership of the

software, other than ownership of the physical media.



Customer acknowledges and agrees that the software is copyrighted and

protected under the copyright laws.



Customer acknowledges and agrees that the software may have been

developed by a third party software supplier named in the copyright

notice(s) included with the software, who shall be authorized to hold the

Customer responsible for any copyright infringement or violation of this

License Agreement.

part

in

Customer



the

of

transfer

agreement

may

of

transfer

of

the

all

third

rights

their

party

in

rights

to

the

and only

bound by

be

software to

a third

if Customer

the terms

party only

obtains the

of this

as

prior

License

Agreement.

Sublicensing and

Distribution

Termination

Upon



terminated

deliver

Transfer



lower

made

be

Hewlett-P



Customer

adaptations

a

such

and

them

to a

contractor in

tier

only upon

ackard.

may not

of

transfer

that

the

to

government

.

.S

U

sublicense

software

the

Customer

,

they

third

connection

their

will

party

prior

to the

agrees

either

.

department

written

the

that

destroy

with

agreement

software

public in

copies

their

agency

or

government

.

.S

U

a

to

distribute

or

physical media

to

or

terms

copies

adaptations

and

prime

a

contract

required

or by

or

by

or

software

the

in

rights

their

telecommunication without the prior written consent of Hewlett-Packard.



Hewlett-Packard may terminate this software license for failure to comply

with any of these terms provided Hewlett-Packard has requested Customer

to cure the failure and Customer has failed to do so within thirty (30) days

.

of such

notice

are

or

shall

viii

Updates and Upgrades



Customer agrees that the software does not include future updates

and upgrades which may be available for HP under a separate support

agreement.

Export



Customer agrees not to export or re-export the software or any copy or

adaptation in violation of the U.S. Export Administration regulations or

other applicable regulations.

ix

Limited Warranty

Software

Media

Notice of Warranty

Claims

Hewlett-Packard warrants for a period of one (1) year from the date of

purchase that the software product will execute its programming instructions

when properly installed on the spectrum analyzer instrument indicated

on this package. Hewlett-Packard does not warrant that the operation of

the software will be uninterrupted or error free. In the event that this

software product fails to execute its programming instructions during the

be

the

of

use

any

remedy

amount

price

card

warranty

period,

(\media")

replace

be

a

time

free

period

be

to

remedy

and

ackard

from

prove

to

ackard

Customer's

,

unable

alternate

product

Hewlett-P

to

for

media

shall

Hewlett-P

of

upon return

Hewlett-P

to

all

defects

one

of

to

return

the

of

Customer's

ackard for

the media

be

shall

.

copies

warrants

in

year

(1)

defective

be

media

the

unable

be

alternate

product

remedy

replacement. Should

within a

refund

a

media upon

the

materials

the

from

during

Hewlett-P

to

replace

to

remedy

all

and

return

to

be

shall

reasonable amount

purchase

the

of

purchase

period,

for

within

refund

a

be

this

workmanship

and

date

warranty

the

ackard

the

shall

.

copies

which

of

media

measurement

the

Hewlett-Packard

of time

upon

price

product

under

In the

.

is

normal

event

Customer's

replacement.

reasonable

a

purchase

the

of

Customer's

,

return

recorded

Should

Customer must notify Hewlett-Packard in writing of any warranty claim not

later than thirty (30) days after the expiration of the warranty period.

Limitation of Warranty

Hewlett-Packard makes no other express warranty, whether written or oral,

with respect to this product. Any implied warranty of merchantability or

have

.

other

tness

This

limited

is

warranty

to

gives

specic

legal

rights

year

(1)

one

the

rights which vary from state to state

duration

of

and Customer

,

, or province

written warranty

this

may

to province

also

.

x

Exclusive Remedies

The remedies provided above are Customer's sole and exclusive remedies.

In no event shall Hewlett-Packard be liable for any direct, indirect, special,

incidental, or consequential damages (including lost prot) whether based on

warranty, contract, tort, or any other legal theory.

Warranty Service

Warranty service may be obtained from the nearest Hewlett-Packard sales

oce or other location indicated in the owner's manual or service booklet.

xi

Contents

1. Installing the Personality

To Install From the Memory Card . . . . . . . . . . .

To Install From a 3.5-inchDiskette Drive . . . . . . . .

If a Memory Error is Displayed . . . . . . . . . . . .

2. Performing Measurements

Calibrating the Optical Spectrum Analyzer . . . . . . .

optical

T

a

ually

the

an

est

the

HP

.

.

test

an

test

Program

o

T

o

T

Running

o

T

o

T

Conguring

Programming

3.

calibrate

calibrate

automatically

man

ectrum

sp

71450A/1A

.

.

.

.

.

amplier

an

amplier

.

.

.

analyzer

.

.

.

.

.

.

.

1-4

1-6

1-8

2-3

. .

. .

. .

.

.

.

.

.

.

.

.

.

. .

. .

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

2-4

.

2-13

.

2-23

2-26

.

.

2-31

2-37

.

Reference

4.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

at

av

gain p

.

.

.

.

.

Calculations .

t

Noise Figure

elngth and

eak .

Po

. .

.

.

Traces

er

w

.

.

. .

.

.

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

Map

u

Men

Messages

Error

Measuremen

Gain and

Laser W

WL

Gain at gain peak . . . . . . . . . . . . . . . . .

NF at gain peak . . . . . . . . . . . . . . . . . .

Bandwidth (3dB) . . . . . . . . . . . . . . . . .

Characteristic Measurement Uncertainty . . . . . . . .

Index

. .

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

.

4-3

.

.

. .

.

.

.

.

4-4

4-5

.

4-5

.

4-6

.

4-6

.

4-7

4-7

4-7

4-8

Contents-1

Contents

1

Installing

the

ersonality

P

Installing the Personality

Use the procedures in this chapter to install the personality. Copies of the

program are included in the following forms:



Memory card.



3.5-inch diskette.

(HP-LIF format)

Do you have an HP

70004A

display?

Installing on HP

71450A/1A optical

spectrum analyzers

YES Install the personality from the memory card. Refer to \To install

from the memory card" in this chapter.

drive

disk

internal

lasts

in

for

ackard

P

HP-IB

this

battery

several

chapter

loses

years.

service

power

center

NO

Battery

Once

the

replace

P

installed,

program

the

Install

Refer

ower

the

erased

is

internal

the

\T

to

program

battery

from

personality

stored

is

memory

return

from

.

the

install

o

,

3.5-inch

a

from

use

the

,

analyzer

directly

battery-powered memory

in

With normal

optical spectrum

an

the

dikette

.

internal

to

external

drive"

the

If

battery

Hewlett

a

The EDFA Noise Gain Prole Personality can be installed in HP 71450A/1A

optical spectrum analyzers if the HP 70953A upgrade kit is installed.

.

.

,

o

T

.

1-2

Installing the Personality

Chapter Contents

To install from the memory card

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

To install from a 3.5-inch diskette drive

If a memory error is displayed

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

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

1-4

1-6

1-8

1-3

To Install From the Memory Card

1. Press

4

5

. If the softkey

USER

EDFA_NG

appears, the personality is

already installed. Continue with Chapter 2 to learn how to perform

measurements.

2. Locate the memory card containing the program.

3. Locate the arrow printed on one end of the card.

4. Insert the card into the HP 70004A display's front-panel card slot. Match

NNNNNNNNNNNNNNNNNNNNNNN

the

card's

arrow

with

the

arrow

printed

above

the card

slot.

5.

6.

7.

8.

1-4

Press

Press

Press

Press

4

N

4

NNNNNNNNN

and

5

Y

DISPLA

N

N

N

N

NN

N

N

N

N

msi

MENU

then

and

5

and then the left-side

NNNNNNNNNNNNNNNNNNNNNNNNN

MORE 1 of 3

the

then

N

N

N

N

NN

N

N

N

N

N

MEMORY

N

and then

left-side

N

NN

N

N

N

N

N

N

N

N

N

N

NN

N

N

N

N

N

N

N

CARD

NNNNNNNNN

catalog & MSI

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Storage

Mass

N

N

.

N

NNNNNNNNNNNNN

Misc

softkey.

NNNNNNNNNNNNNNNNNNNNNNNNN

NNNNNNN

softkey

.

.

Installing the Personality

To Install From the Memory Card

9.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

HP-MSIB CARD

If

2053 Storage device error

to display all les contained on the memory card.

is displayed, either the card is missing

or the card's HP-MSIB address is listed incorrectly. The HP-MSIB

address for the card is the same address as the display's HP-IB address

and is normally set to 4. If the address is not correct, enter the correct

address using the numeric keypad.

10.

Press the

11. Use the numeric keypad to enter the

this means pressing

The

is

the

If

12.

not

program.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNN

front-panel

being

error

enough

LOAD FILE

LED

copied

into

message

memory

free

\If

to

Refer

softkey.

415

and then

next

the

2011

memory

a

to

4

USER

Memory

the

in

NNNNNNNNNNNNNNNNN

ENTER

card

the

menu.

5

overflow

optical

error

EDFA_NG

.)

slot

spectrum

displayed"

is

le number. (Normally,

lights indicating

displayed,

is

analyzer

in

there is

to

this

that the

load

chapter

le

the

.

1-5

To Install From a 3.5-inch Diskette Drive

When copying programs directly from an external diskette drive, the drive

must be a 3.5 inch, CS80-compatible drive, such as an HP 9122. The diskette

containing the EDFA advanced-measurement program uses the LIF format.

1.

Press

4

5

. If the softkey

USER

NNNNNNNNNNNNNNNNNNNNNNN

EDFA_NG

appears, the EDFA Noise Gain

Prole Personality is already installed. Continue with Chapter 2 to learn

how to perform measurements.

2. Connect a 3.5-inch diskette drive to the MMS mainframe that contains

the

optical

spectrum

analyzer module

.Use

an HP-IB

cable.

N

N

N

N

N

N

N

NN

NN

N

N

message

.

N

N

N

N

N

N

N

.

to

form:

N

diskette drive

N

N

N

N

N

N

softkey

such

the

enter

A.UV

the

Insert

3.

4.

5.

6.

7.

8.

Press

Press

read

to

Press

Press

Press

4

DISPLA

N

N

N

msi

4

MENU

N

N

N

MORE 1

N

N

N

HPIB

drive's address

New addresses

diskette containing

and then

5

Y

N

N

N

N

N

N

N

N

and

N

then

device.

then

and

5

N

N

N

N

N

N

N

N

N

N

N

N

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

N

N

N

N

N

N

N

N

N

of

N

N

N

N

N

N

N

N

DISK

3

N

N

N

N

N

and

,

.

are entered

N

N

N

N

N

N

N

N

HPIB

the

and

use

the program

left-side

the

N

N

N

N

N

N

N

NN

NN

N

N

DISK

left-side

then

the

in the

N

N

N

Mass

N

N

N

N

N

N

N

Ignore

.

N

N

N

N

N

N

N

N

Misc

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

catalog &

numeric

following

N

N

N

N

N

N

N

N

any

N

N

N

N

N

N

N

N

N

NN

N

N

N

keypad

into the

N

N

N

N

N

N

N

Storage

softkey

N

N

N

N

N

N

N

N

MSI

where:

A

is a digit from 0 to 7, representing the drive's HP-IB address.

U

is a digit from 0 to 9, representing the unit number. The unit

number is typically 0 or 1 and refers to an individual disk drive slot.

0.

is

digit

value

from

volume

representing

9,

to

0

the

, for reading diskettes

.So

number

The default

a

V

is

numbers are used for hard disk drives

volume number should be 0. The default value is 0.

3.00

For example

, entering

indicates an address of 3, a unit number of

0 and a volume number of 0. This accesses a diskette in the left drive

of an external diskette drive at HP-IB address 3.

.

.

Unable

as

diskette

Volume

.

, the

1-6

Installing the Personality

To Install From a 3.5-inch Diskette Drive

9. Press the

10.

Press the

11. Use the numeric keypad to enter the

this means pressing

12. If the error message

not enough free memory in the optical spectrum analyzer to load the

program. Refer to \If a memory error is displayed" in this chapter.

NNNNNNNNNNNNNNNNN

ENTER

NNNNNNNNNNNNNNNNNNNNNNNNNNNNN

LOAD FILE

softkey.

softkey.

EDFA_NG

415

and then

2011 Memory overflow

NNNNNNNNNNNNNNNNN

ENTER

.)

le number. (Normally,

is displayed, there is

1-7

If a Memory Error is Displayed

1. Press

2.

3.

4

5

MENU

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

MORE 1 of 3

and then the left-side

and then

Misc

softkey.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

catalog & MSI

.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

INTRNL MEMORY

Notice the

MEM

TOTAL MEM

(available memory) by deleting existing les to free additional

. The following gure shows a typical display.

and

AVAIL MEM

listings.You must increase

AVAIL

memory.Or, if you have an HP 71450A/1A optical spectrum analyer,you

approximately

is

NNNNNNNNNNNNNN

need

may

131000

qualied

to

bytes

service

install

memory

of

personnel.

additional

1

a

,

memory;

memory

MB

Order

the

TOTAL

if

assembly

70953A

HP

MEM

can

upgrade

installed

be

kit.

by

1-8

spectrum analyzer memory conguration.

Optical

2

erforming

P

Measurements

Performing Measurements

Chapter Contents

Calibrating the Optical Spectrum Analyzer

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

To calibrate the optical spectrum analyzer . . . . . . . . . . . ..... 2-4

To calibrate an HP 71450A/1A . . . . . . .................... 2-13

Running a Test

To automatically test an amplier

To manually test an amplier

Conguring

ensure accurate

o

T

calibrations

During

vibration

jarring

and

instrument,

the

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

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

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

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

ensure

o

equipment,

:

.

lightwave

accurate

and

.

instrumentation

measurements

supporting

avoid

structure

and

bumping,

.

the

measurements .

and

movement.

Program

measurements,

T

test

:

:

:

:

:

:

:

:

:

:

:

:

are

setups

test

moving,

2-23

2-26

2-31

2-37

:

:

:

sensitive

otherwise

or

2-3

to

2-2

Guard

due

against

polarization

to

changes

Calibrating the Optical Spectrum Analyzer

Performing a user calibration on the optical spectrum analyzer

ensures maximum wavelength and amplitude accuracy for your EDFA

measurements. User calibrations require a stable (amplitude and wavelength)

single-frequency laser within the 600 to 1700 nm range.You can access the

Calibration menu from the optical spectrum analyzer's

4

5

MENU

and then

NNNNNNNNNNNNNNNNN

Amptd

.)

NNNNNNNNNNNNNNNNN

Amptd

menu. (Press

The optical spectrum analyzer's maximum calibration adjustment is about 2

Illegal

2023,

the

power

a

error

on

calibration,

meter

connected

and

cables

vary

may

sensitive

eects

the

Then, the

.

changes

.

,

the

to

this

of

in wavelength.

nm

signal

Cal

Because

the

calibration

polarization

source's

light

ber-optic

optical

the

polarization,

larger adjustment

If a

displayed.

is

optical spectrum

performed

on

output

the

optical

is

be

power

power

disconnected

analyzer

measured

should

cable

spectrum

analyzer is

persons

by

measurements

measured

rst

is

from

Because

.

the

of

value

is attempted,

slightly

knowledgeable

.

power

the

moving

output

polarization

During

with

meter

ber-optic

power

wavelength

a

Use

or optimum

F

within

results, perform

amplier's

the

calibration

the

range

at

a

wavelength

that

is

within

the

range

amplier

the

of

you are testing.

During a calibration, the optical spectrum analyzer defaults expect a signal within the following limits:

Power .........................................05 dBm65dB

Wavelength ........................................130062nm

calibration

your

amplitude

enter the

must

ou

Y

wavelength

and

of

source

from these

dierent

is

it

if

values.

2-3

Performing Measurements

Calibrating the Optical Spectrum Analyzer

To calibrate the optical spectrum analyzer

Ensuring amplitude accuracy

During this procedure, avoid moving the ber-optic cables whenever possible. Moving ber-optic cables

changes the polarization of the light which aects power measurements.

source

Measure

the

wavelength

Measure the average

power

following

The

11896A

HP

The

optical

spectrum

71450A/1A"

Measure

1.

wavelength

The

the

the

procedure

the

is

analyzers

chapter

this

in

wavelength

the

meter

must

laser

optical

spectrum

wavelength

requires

suggested

perform

.

Enter

.

a

have

analyzer's

air

in

as

power

a

polarization

the

precision

a

of

wavelength

the

wavelength

.

and

meter

controller

in

listed

steps

single-mode

the

in

between

600

monochromator

polarization

a

or

F

.

calibrate

o

\T

laser

provided

space

1700

to

air

is

HP

lled,

controller

71450A/1A

an

a

using

nm.

measure

HP

below

Because

wavelength: nm

2. Connect the laser, polarization controller, and power meter as shown in

the following gure.

.

.

2-4

Performing Measurements

Calibrating the Optical Spectrum Analyzer

accurate

For

not

Do

procedure

Adjust

3.

on

measurements

disconnect

.

cable

Maintaining

the polarization

the power

or

1

connection

this

meter.

from

2

cable

ensures

controller to

Record the

the laser

the

power

polarization

or

greatest

achieve

level

controller

measurement

maximum

the

the

on

during

.

accuracy

following

calibration

the

power

line:

reading

maximum power: dBm

4. Adjust the polarization controller to achieve a minimum power reading on

the power meter. Record the power level on the following line:

minimum power: dBm

and

3

steps

Calculate

5.

the

using

4

averag e power

average

the

following

minimum power

=

the two

of

equation.

power

Record

+

readings

the result

maximum power

2

average

recorded

below:

power:

in

dBm

2-5

Performing Measurements

Calibrating the Optical Spectrum Analyzer

6. In the test setup, replace the power meter with the optical spectrum

analyzer as shown in the following gure. Be sure to use two cables and

an adapter to connect the optical spectrum analyzer to the polarization

controller.

7. Turn the laser on.

For accurate measurements

Do not disconnect cable 3 from the optical spectrum analyzer during or after the calibration procedure.

Maintaining this connection ensures the greatest measurement accuracy, since your optical spectrum

adapter

analyzer

replaced

be calibrated

will

with

aber

splice

splice measurements,

fusion

or

F

3.

cable

of

end

free

the

at

.

the

2-6

is

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Determine correction

factor for source

spontaneous emission

8. Press

9. Press

10. Press

4

INSTR PRESET

4

AUTO MEAS

4

AUTO ALIGN

5

.

5

to display the laser's response.

5

to align the optical spectrum analyzer.

11. If the instrument you are calibrating has the Option 051 personality,

perform the following steps:

N

.

NNNNNNNNNNNNN

EDFA

to start the EDFA test personality.

a.

b.

Press

4

USER

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

Output Test

5

and then

c. Locate the peak of the spontaneous emission. Adjust the wavelength

spontaneous

of

dB

10

peak,

this

of

side

either

on

that,

so

span

.

visible

the

is

change

to

4

SP

AN

5

key along

with

front-panel

the

knob

emmision

Use

span.

the

Span adjusted for proper

Press

NNNNNNNNNNNNNNNNN

Setup

and then

d.

spontaneous emmission levels.

NNNNNNNNNNNNNNNNNNNN

INTEGRT START

NNNNNNNNNNNNNNNNNNNNNNNNN



NN

.

2-7

Performing Measurements

Calibrating the Optical Spectrum Analyzer

e. Use the front-panel knob to move the left-integration marker to the

left edge of the display.

f.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

INTEGRT STOP, and use the front-panel knob to move the

right-integration marker to the right edge of the display.

g.

h.

i. Subtract the

er

pow

1

the

Press

the

When

and

Integrt ASE

of

ratio

=

dB

)

(

left-side

measurement

two

the

utput

O

N

Measure

is complete

Amplr

softkey

, record

measurements on the following lines:

Output Pwr

Integrt ASE

Integrt ASE

power

r

w

P

(

dB

levels

)

m

from the

. Record

Integ

0

Output Pwr

result

the

E

AS

t

r

.

the displayed

: dBm

: dBm

to determine the

following

the

on

)

m

dB

(

Output Pwr

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

1 power: dB

12. If the instrument you are calibrating does not contain the Option 051

personality, perform the following steps:

a. Record the

value of the signal peak on the following line:

2-8

line:

Performing Measurements

Calibrating the Optical Spectrum Analyzer

b. Press

4

NORMAL On/O

Output Pwr

5

, and use the front-panel knob to place the

: dBm

marker on the maximum level of the spontaneous emission spectrum.

c.

NNNNNNNNNNNNNNNNNNN

N

Press

Marker

NNNNNNNN

On

is underlined.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

,

MORE 1 of 4

, and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

MKNOISE On Off

so that

d. Record the marker value on the following line:

e.

f.

g.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

Press

MKNOISE On Off

N

N

N

N

N

N

N

N

N

N

Press

MORE 2

NN

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

MKR BW

marker

Record

On Off

bandwidth

the

N

N

N

N

NN

NN

NN

N

N

N

N

N

of

N

N

N

N

N

N

N

N

N

N

NN

NN

displayed

N

N

N

N

N

N

N

N

N

4

N

N

so that

is

N

N

N

N

N

N

N

N

,

mkr bw/

set

Marker

so that

NN

NN

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

On

is

3

0

to

Bandwidth

MKR

NNNNNNNNNN

N

Off

is underlined.

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

zoom

underlined. Make

.

dB

: dBm/nm

noise

N

NN

NN

NN

bw

,

and

then

sure that

value:

the

MKRBW: nm

record

and

,

BW

above

)

ASE

:

Calculate

h.

ASE

E

AS

(

on

dB

the

m

the

)

=

ASE

line

M

using

below:

R

K

noise

the

+

values

10

og

l

recorded

(

K

M

Integrt

R

the

dBm

log

ASE

of the

to



1

so that

to

the

0

Integrt

i. Subtract

to

the

1

power(dB)=Output P wr(dBm)0

j.

Press

the

Use

13.

broadband

the

determine

following

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

N

the ratio

line:

MKR BW On Off

following

power

equation

meter

measurement:

f actor

=10

wherexis the 1 power recorded in step

from

12h)

(step

two power

levels.

Integ rt ASE(dBm

NNNNNNNNNN

N

Off

is underlined.

correction factor

calculate

narrow

the

band



1

x

10

10

+1

11i or 12i.

the

Output

Record

Pwr

the

result

on

12a)

(step

)

1 power: dB

the

for

optical

spectrum

analyzer

2-9

Performing Measurements

Calibrating the Optical Spectrum Analyzer

source spontaneous emission correction factor: dB

Total the correction

factors

Calculate

power

Measure

power

corrected

level

the

OSA

on

average

14. Power meters generally are calibrated with an open beam of light. By

simply using a ber adapter, they will measure the optical power in

the beam emerging from the ber end. This is lower than the power in

the ber by 3.6%. If you wish to have power measurements relative to

open-beam power emerging from the ber, enter a correction factor of

+0.16 dB. If you wish to have power measurements relative to power in

the ber, enter 0 dB.

correction factor: dB

sign

the

of

track

keep

to

sure

Be

14.

and

13

steps

.

recorded

result

the

SEARCH

and

,

5

SEARCH

and enter

5

,

from

enter

in

the

on

then

and

5

wavelength

a

then

and

5

a wavelength

total correction

15

step

following

corrected

4

TO

4

TO

the

to

line

CENTER

span

CENTER

span of

average

.

power

.

5

1

of

.

5

0

factor:

power

level:

nm.

nm.

recorded

in

dd

15. A

each number

dd

A

16.

Record

5.

Press

17.

Press

18.

Press

19.

20. Press

the

the

4

4

4

4

values

value

PEAK

AN

SP

PEAK

AN

SP

of

dB

step

dBm

21. Press

22.

23.

24.

25.

26. A

4

5

.

MENU

NNNNNNNNNNNNNNNNN

Press the left-side

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

LOG dB/DIV,415

.

scale

left-side

the

Press

NNNNNNNNNNNNNNNN

Press

SWPTIME AutoMan

Amptd

N

N

N

NN

N

N

N

BW,Swp

NNNNNNNNNNNNNNNNNNNNNNNNN

, and

N

N

N

N

N

NNNNNN

softkey.

N

N

N

NN

N

N

,

NNNNNNNN

dB

to select a 1 dB logarithmic amplitude

softkey

.

NNNNN

4

5,4

5

1

, and then

0

s

.

djust the polarization controller to \peak" the trace displayed on the

optical spectrum analyzer

.

This sets the polarization for a maximum power reading.

2-10

Performing Measurements

Calibrating the Optical Spectrum Analyzer

27. Press

4

PEAK SEARCH

5

, and record the power level indicated by the marker:

maximum power: dBm

28. Press

415

.

29. Adjust the polarization controller to \dip" the trace displayed on the

optical spectrum analyzer to a minimum power value.

30. Record the absolute value of the 1 marker's power ratio on the following

line:

1 power: dBm

31. Use the values recorded in steps 27 and 30 to calculate the average

displayed

power

as

shown

following equation.

the

in

Record the

result

below:

er

pow

1

0

er

pow

N

N

N

N

N

N

softkey

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

controller

power level

N

of

N

.

N

N

N

N

N

N

to

N

N

N

N

and

,

4

achieve

recorded

2

average

then

displayed

a

in

power:

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

AMETER

31.

step

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

N

N

Off

On

Amplitude

N

N

N

N

N

so

Meter

32.

33.

34.

er

av

Press

Press

that

Adjust

power

=

er

pow

e

ag

left-side

the

N

N

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

MORE 1

N

N

N

N

NN

N

N

On

of

underlined.

is

the polarization

level equal

maximum

N

N

N

N

NN

N

N

N

N

N

Amptd

N

N

N

N

N

N

N

N

N

N

N

N

,

4

MORE 2

to the

N

Ensuring amplitude accuracy

It is very important not to move the ber-optic cables during the remaining steps of this procedure.

2-11

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Enter the calibration

power and wavelength

35. Press the left-side

NNNNNNNNNNNNNNNNNNNNNNNNNN

cal menu

NNNNNNNNNNNNNNNNNNNNNNNNNNNNN

,

cal setup

NNNNNNNNNNNNNNNNNNNN

Waveln

,andthen

softkey. Then, press

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

POWER FOR CAL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

MORE 1 of 2

.

,

36. Use the numeric keypad to enter the corrected power level calculated in

step 16.

37.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

WAVELEN FOR CAL

Then, press

NNNNNNNNNNNNNNNNNNNNNNNNNNNNN

prev menu

. Enter the wavelength recorded in step 1.

and then

NNNNNNNNNNNNNNNNNNNNNNN

CAL ALL

.

2-12

Performing Measurements

Calibrating the Optical Spectrum Analyzer

To calibrate an HP 71450A/1A

Ensuring amplitude accuracy

During this procedure, avoid moving the ber-optic cables whenever possible. Moving ber-optic cables

changes the polarization of the light which aects power measurements.

ROM

Determine

the

version

Measure the source

wavelength

polarization

a

and

version

enter

to

N

N

NN

service

The

.

above,

or

meter

on

N

N

N

N

N

N

N

N

N

version

controller

used

is

instrument.

the

Miscellaneous

the

N

N

N

N

N

N

N

N

N

N

softkeys

of

not

do

o calibrate

in \T

.

select

to

.

ROM

the

perform

which

menu.

is

this

the

following

The

11896A

HP

The

optical

The

calibration

Press

1.

2.

Press

3.

Press

upper

the

the ROM

If



procedure

procedure

is

spectrum

procedure

left-side

the

N

N

N

N

N

N

NN

the

MORE

N

N

N

N

N

N

N

N

the

ROM

right

.

suggested

the

analyzer's

should

N

N

N

N

N

N

Misc

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

of

1

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

N

VERSION

corner

version is

Instead,

requires

be

N

N

N

NN

N

N

N

softkey

N

N

N

N

N

N

N

N

and then

3

N

N

N

N

N

N

N

N

N

softkey

of the

B.05.00

perform

power

a

polarization

ROM

performed

display.

the steps

spectrum analyzer" in this chapter.



If the ROM version is

B.04.04

or below, continue with this procedure.

4. Measure the wavelength of a precision single-mode laser using a

wavelength

laser

The

meter

must

Enter

.

have

wavelength

the

wavelength

a

in

between

600 to

1700

nm.

provided

space

the

the optical spectrum analyzer's monochromator is air lled, measure

the wavelength as in air

.

controller

displayed

optical

below

Because

.

in

.

wavelength: nm

2-13

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Measure the average

power

5. Connect the laser, polarization controller, and power meter as shown in

the following gure.

accurate

For

not

Do

procedure

measurements

disconnect

Maintaining

.

cable

1

this

cable

or

connection

2

from

ensures

the

laser

the

greatest

or polarization

measurement

controller

accurac

during

y

.

the

calibration

6. Adjust the polarization controller to achieve the maximum power reading

on the power meter. Record the power level on the following line:

maximum power: dBm

7.

djust

A

the

the

power

polarization

Record

.

meter

controller

power

the

achieve a

to

level on

minimum

following

the

power

reading

line:

minimum power: dBm

8. Calculate the average

7 using the following equation. Record

minimum power

averag e power

=

of the two power readings recorded in steps 6 and

the result below:

+

maximum power

2

2-14

on

Performing Measurements

Calibrating the Optical Spectrum Analyzer

average power: dBm

9. In the test setup, replace the power meter with the optical spectrum

analyzer as shown in the following gure. Be sure to use two cables and

an adapter to connect the optical spectrum analyzer to the polarization

controller.

10. Turn the laser on.

For accurate measurements

Do not disconnect cable 3 from the optical spectrum analyzer during or after the calibration procedure.

optical spectrum

your

since

,

y

or fusion

F

accurac

splice

measurements,

the

adapter

is

Maintaining this

analyzer will

replaced with

connection

calibrated

be

ber

a

splice

ensures

the

at

.

free

the

greatest

end

cable

of

measurement

3.

2-15

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Determine correction

factor for 0.2 nm RBW

11. Press

12. Press

13. Press

4

AUTO MEAS

4

AUTO ALIGN

4

RES BW

5

, and enter a 0.2 nm bandwidth.

5

to display the laser's response.

5

to align the optical spectrum analyzer.

14. Record the source amplitude on the following line:

power (0.2 nm RBW): dBm

15. Press

4

RES BW

5

, and enter a 0.5 nm bandwidth.

16. Record the source amplitude on the following line:

power (0.5 nm RBW): dBm

reading

the

from

16

step

17.

cor

N

This

Subtract

the result

ection

r

E

T

O

number

the

on the

actor

f

should be

reading

in

following line:

E

W

O

P

=

between 0

dB

R

0.2

and

step

nm

0

14

0.2

0

RB

W

dB

W

O

P

correction

.

R

E

step

16

factor:

in

step

14

and

record

dB

Determine correction

factor for source

spontaneous emission

18. Press

4

INSTR PRESET

5

.

19. If the instrument you are calibrating has the Option 051 personality,

perform the following steps:

N

N

N

NN

N

N

N

N

N

N

N

N

a.

b.

Press

Press

4

USER

N

N

N

N

N

N

N

N

N

N

N

NN

Output

and then

5

N

N

N

N

N

N

N

N

N

NN

Test

c. Locate the peak of the spontaneous emission. A

N

to start

EDFA

N

N

N

N

N

N

N

N

NN

N

the

personality

test

A

EDF

.

.

djust the wavelength

span so that, on either side of this peak, 10 dB of spontaneous

emmision

is visible.

2-16

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Span

d.

Use the

span.

adjusted

Press

for

N

N

N

N

N

N

NN

NN

Setup

4

SPAN

N

N

N

N

5

key along with the front-panel knob to change the

N

N

N

N

N

levels.

N

N

N

N

N

N

NN

NN

N

START

N

N

N

N

N

N

N

N

N

N

N

N

.



proper

N

N

N

,

spontaneous

then

and

emmission

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

INTEGRT

N

N

Use the

e.

front-panel knob

to

left-integration

the

move

left edge of the display.

f.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

INTEGRT STOP, and use the front-panel knob to move the

right-integration marker to the right edge of the display.

marker

to

the

2-17

Performing Measurements

Calibrating the Optical Spectrum Analyzer

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

Press

g.

Measure

Amplr

.

measurement

the

When

h.

measurements

Integrt

and

Pwr

Subtract the

i.

two

of the

ratio

1

power(dB)=Output P wr(dBm)0

ASE

Integrt

power

ASE

levels

completed,

is

Integrt

Output

the

from

Record

.

Integrt ASE(dBm

record

the

on

Output

result

the

displayed

the

following

:

Pwr

:

ASE

to

Pwr

on

)

determine

the

Output

lines:

the

following

1 power: dB

20. If the instrument you are calibrating does not contain the Option 051

personality,

a. Record

b. Press

4

NORMAL On/O

perform

value

the

following

the

signal

the

of

5

, and use the front-panel knob to place the

steps:

peak

following

the

on

Output Pwr

line:

:

marker on the maximum level of the spontaneous emission spectrum.

2-18

dBm

dBm

line:

dBm

Performing Measurements

Calibrating the Optical Spectrum Analyzer

c.

NNNNNNNNNNNNNNNNNNNN

Press

Marker

NNNNNNNN

On

is underlined.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

,

MORE 1 of 4

, and then

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

MKNOISE On Off

d. Record the marker value on the following line:

MKR

e.

f.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

MKNOISE On Off

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

MORE 2 of 4

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

MKR BW On Off

so that

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

,

mkr bw/ zoom bw

so that

NNNNNNNN

On

is underlined. Make sure that the

NNNNNNNNNNN

Off

noise

is underlined.

, and then

marker bandwidth is set to03dB.

Record the

g.

displayed

Marker

Bandwidth

value:

MKRBW: nm

og

l

recorded

(

K

M

)

R

W

B

Calculate

h.

ASE

E

AS

(

on

dB

the

m

the

)

=

ASE

line

M

using

below:

R

K

noise

the

+

values

10

Integrt

the

from

12i)

(step

ratio

ASE

of

the

two

power

levels

Subtract

i.

to

the

the

determine

following

Integrt

the

line:

so that

: dBm/nm

record the

and

,

above

:

ASE

Output

Record

.

Pwr

the

(step

result

dBm

12a)

on

Output

=

)

dB

(

er

pow

1

NN

NN

N

N

N

N

j.

N

Press

MKR BW On Off

Pw

power:

1

N

N

N

N

N

NN

NN

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

so that

NN

NN

NN

N

N

N

N

N

Off

is underlined.

)

m

dB

(

E

AS

t

r

nteg

I

0

)

m

dB

(

r

21. Use the following equation to calculate the correction factor for the

broadband power meter to the narrow band optical spectrum analyzer

measurement:

actor

f

=

10



og

l

0

1

10

10

x



1

+1

wherexis the 1 power recorded in step 19i or 20i.

source spontaneous emission correction factor: dB

dB

2-19

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Total the correction

factors

Calculate

power

Measure

power

corrected

level

the

OSA

on

average

22. Power meters generally are calibrated with an open beam of light. By

simply using a ber adapter, they will measure the optical power in

the beam emerging from the ber end. This is lower than the power in

the ber by 3.6%. If you wish to have power measurements relative to

open-beam power emerging from the ber, enter a correction factor of

+0.16 dB. If you wish to have power measurements relative to power in

the ber, enter 0 dB.

correction factor: dB

23. Add the values from steps 17, 21, and 22. Be sure to keep track of the

sign of each number.

factor:

step

power

recorded

in

level:

.

nm.

1

of

.

nm.

0

of

dd

A

24.

Record

8.

Press

25.

Press

26.

Press

27.

28. Press

the

4

4

4

4

value

PEAK

AN

SP

PEAK

AN

SP

result

the

SEARCH

and

,

5

SEARCH

and

5

,

recorded

on

and

5

enter

and

5

enter

23

step

in

following

the

corrected

4

then

TO

wavelength

a

4

then

TO

wavelength

a

total

to

CENTER

CENTER

correction

average

the

.

line

power

5

span

5

span

dB

dBm

29. Press

30.

31.

4

MENU

the

Press

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

LOG dB/DIV,415

5

.

left-side

NN

NN

NN

N

N

N

N

Amptd

N

N

N

N

N

NN

, and

softkey

NNNNNNNN

dB

.

to select a 1 dB logarithmic amplitude

scale.

NNNNNNNNNNNNNNNNNNNN

32. Press the left-side

N

N

N

N

N

N

N

N

NN

N

N

N

N

N

33.

34. A

N

Press

SWPTIME

djust the polarization controller

optical spectrum analyzer

N

N

N

N

N

NN

N

N

BW,Swp

N

N

N

N

N

N

N

N

N

NN

N

N

N

N

N

N

AutoMan

N

N

NN

N

.

softkey.

4

,

,

5

1

4

5

0

,

and

then

to \peak" the trace displayed on the

This sets the polarization for a maximum power reading.

35. Press

4

PEAK SEARCH

record the power level indicated by the marker:

5

,and

2-20

N

N

N

N

N

.

s

Performing Measurements

Calibrating the Optical Spectrum Analyzer

maximum power: dBm

36. Press

415

.

37. Adjust the polarization controller to \dip" the trace displayed on the

optical spectrum analyzer to a minimum power value.

38. Record the absolute value of the 1 marker's power ratio on the following

line:

1 power: dBm

39. Use the values recorded in steps 35 and 38 to calculate the average

displayed power as shown in the following equation. Record the result

below:

power

1

0

er

pow

N

N

NN

NN

softkey

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

2

controller

power

N

N

N

N

N

of

level

.

N

N

N

NN

N

N

4

to

average

N

N

and

,

achieve

recorded

2

N

N

then

A

a displayed

in step

power:

N

N

N

N

N

N

N

N

NN

N

METER

N

On

Off

N

N

N

N

N

N

N

N

N

N

N

N

NN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

Amplitude Meter

39.

N

N

so

40.

41.

42.

aver

Press

Press

that

djust

A

power

age

the

N

N

MORE

N

N

N

N

N

On

N

N

NN

N

N

N

N

the

level

=

power

left-side

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

of

1

underlined.

is

polarization

equal

maximum

N

N

N

N

N

N

N

N

N

N

N

Amptd

N

N

N

N

N

NN

N

N

N

N

N

,

4

MORE

the

to

Ensuring

amplitude

accuracy

It is very important not to move the ber-optic cables during the remaining steps of this procedure.

2-21

Performing Measurements

Calibrating the Optical Spectrum Analyzer

Enter the calibration

power and wavelength

43. Press the left-side

NNNNNNNNNNNNNNNNNNNNNNNNNN

cal menu

NNNNNNNNNNNNNNNNNNNNNNNNNNNNN

,

cal setup

NNNNNNNNNNNNNNNNNNNN

Waveln

,andthen

softkey. Then, press

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

POWER FOR CAL

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

MORE 1 of 2

.

,

44. Use the numeric keypad to enter the corrected power level calculated in

step 24.

45.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

WAVELEN FOR CAL

Then, press

NNNNNNNNNNNNNNNNNNNNNNNNNNNNN

prev menu

. Enter the wavelength recorded in step 4.

and then

NNNNNNNNNNNNNNNNNNNNNNN

CAL ALL

.

2-22

Running a Test

After you've calibrated the optical spectrum analyzer (as explained in the

previous section), you're ready to make measurements. Two testing modes

are available: automatic and manual. Although both testing modes perform

the same measurement, the manual mode allows you to use EELED noise

sources that can not be externally modulated by a TTL signal. Manual mode

pauses the program so that you can manually turn on or o the EELED noise

source.

the

softkeys

The

order that

the testing

during \auto"

the measures

then

and

the measurement.

progress

of

the

both

in

testing, the

\auto"

should be

operator adjusts

the EDF

A.

\manual"

and

done|from top

the laser

During

testing,

menus

bottom.

to

display

are

measures

,

displayed

or

F

messages

in

example

EELED

the

show

,

the

2-23

Performing Measurements

Running a Test

EDFA testing requires the following test setup.

2-24

Performing Measurements

Running a Test

Set the laser for the

desired average power

level

The EDFA TDE personality measures the average ASE power level resulting

from a modulated laser's average power. Before you begin testing an EDFA,

determine the average power level of the laser input desired for your

application. Next, set the test laser's unmodulated power level 3 dB higher

than this level. For example, if the modulated laser's power into the amplier

is010 dBm, set your test laser's output power to07 dBm. When modulated

at the 50% duty cycle, the test laser's power will be equal to the level used in

your application.

The following gure shows the timing required to measure the average ASE

value from an input laser saturating the EDFA. The laser is modulated at a 25

kHz rate and 50% duty cycle. In this example, the laser's average power is

dBm

8

0

the data

laser's o

the gure

in

see

decreases

and

average

the

.

laser

dBm

8

0

(

s after

10



cycle and

when the

ASE

=

, the

level

dBm

5

0

the laser

in the

region where

power

ASE

laser turns

for the

3

0

turned

is

given

dB).

level

on.

average

optical

The

This

o.

the

increases

Measuring

input

ASE

spectrum

point

varies

when

the

power

analyzer samples

way

half

is

laser

of

.

is

10

at

modulated

the

linearly

the

ASE

through

you

As

turned

provides

s



the

can

o

Timing diagram showing EELED noise source.

2-25

Performing Measurements

Running a Test

To automatically test an amplier

Connect the equipment

1. Connect the equipment as shown in the following gure.

2. Turn on the equipment.

3. Do the following steps to modulate the HP 8168A/B/C laser at a 25 kHz

rate:

a.

Press

front-panel

the

4

VELENGTH

A

W

5

key

,

and

enter

the

desired

wavelength.

b. Press the

NNNNNNNNNNNNNNNNNN

N

c.

d.

N

Press

Mod/CW

Toggle the

4

OUTPUT PO

5

key, and enter the source power

WER

to turn the modulation on.

NNNNNNNNNNNNNN

NNNNNNNNNNNNNNNNN

Freq

/

Power

softkey so that

NNNNNNNNNNNNNNNNN

FREQ:

is selected.

.

2-26

Performing Measurements

Running a Test

Adjust the laser for the

desired drive level to

the EDFA

The softkey label reads

Power

.

e. Enter a modulation value of 25 kHz.

4. Turn the laser on.

NNNNNNNNNNNNNNNNN

5. On the optical spectrum analyzer, press the front-panel

6.

Press

4

USER

NNNNNNNNNNNNNNNNNNNNNN

N

5

,

EDFA_NG

, and then

NNNNNNNNNNNNNNNN

N

setup

.

4

AUTO MEAS

5

key.

7. Perform the following steps if you need to change the optical spectrum

analyzer's tuning range:

.

a.

b.

Use

Press

the

4

4

HOLD

CENTER

.

5

5

and

4

SP

AN

5

keys

to

change

the

range

8.

9.

N

N

N

Press

auto

NNNN

Press

ADJUST LASER

N

N

N

N

NN

N

N

N

N

N

.

NNNNNNNNNNNNNNNNNNNNNNNNN

NNNNNNNNN

and then

NNNNNNNNNN

NNNN

ZOOM

.

2-27

Performing Measurements

Running a Test

10.

Adjust the laser power for the desired drive level. Then, press

NNNNNNNNNNNNNN

DONE

NOTE

The laser power measured by the personality is the average power of the laser at the adapter. This

will be less than the power setting on the tuned laser source by typically 7 dB (3 dB for average

versus peak power and 4 dB loss in the coupler).

.

2-28

Performing Measurements

Running a Test

Measure the EELED

11. Press

12. Wait until the message

MEASURE EELED

.

Noise source measurement complete

is

displayed.

13. Remove the adapter, and insert the EDFA as shown in the following

gure.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

14. Press

MEASURE EDFA

.

15. Wait approximately one minute for the measurement to complete.

the

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

traces

gure

noise

and

gain

The

gain

The

.

following

gure

wavelength for convenience

the screen, press

or use the knob or

4

NORMAL ON/OFF

step keys

displayed as

are

markers are

NF

and

o move the markers to any

.T

5

, and enter the desired wavelength

positioned

.

shown

in

the

at

position on

laser

2-29

Performing Measurements

Running a Test

Gain

and

noise

gure

measurement

results.

2-30

To manually test an amplier

Performing Measurements

Running a Test

Connect the equipment

1. Connect the equipment as shown in the following gure.

2. Turn on the equipment.

3. Do the following steps to modulate the HP 8168A/B/C laser at a 25 kHz

rate:

a.

Press

front-panel

the

4

VELENGTH

A

W

5

key

,

and

enter

the

desired

wavelength.

b. Press the

NNNNNNNNNNNNNNNNNNN

c.

d.

N

Press

Mod/CW

Toggle the

4

OUTPUT POWER

5

to turn the modulation

NNNNNNNNNNNNNN

Freq

/

NNNNNNNNNNNNNN

Power

NNN

softkey so that

key, and enter the source power

on.

NNN

NNNNNNNNNNNNNN

FREQ:

is selected.

.

2-31

Performing Measurements

Running a Test

Adjust the laser for the

desired drive level to

the EDFA

The softkey label reads

Power

.

e. Enter a modulation value of 25 kHz.

4. Turn the laser on.

NNNNNNNNNNNNNNNNN

5. On the optical spectrum analyzer, press the front-panel

6.

Press

4

USER

NNNNNNNNNNNNNNNNNNNNNN

N

5

,

EDFA_NG

, and then

NNNNNNNNNNNNNNNN

N

setup

.

4

AUTO MEAS

5

key.

7. Perform the following steps if you need to change the optical spectrum

analyzer's tuning range:

.

a.

b.

Use

Press

the

4

4

HOLD

CENTER

.

5

5

and

4

SP

AN

5

keys

to

change

the

range

8.

2-32

On

the

optical

spectrum

analyzer

press

,

N

N

N

N

NN

N

N

N

N

N

N

N

N

manual

N

N

N

N

N

N

.

Performing Measurements

Running a Test

9.

10.

NOTE

The laser power measured by the personality is the average power of the laser at the adapter.This

will be less than the power setting on the tuned laser source by typically 7 dB (3 dB for average

versus peak power and 4 dB loss in the coupler).

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Press

ADJUST LASER

Adjust the laser power for the desired drive level. Then press

and then

NNNNNNNNNNNNNN

ZOOM

.

NNNNNNNNNNNNNN

DONE

.

2-33

Performing Measurements

Running a Test

Perform the

measurement

11. Turn on the EELED noise source.

12. Press

13. Wait until the message

14. Remove the adapter, and insert the EDFA.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

MEASURE Nsource

displayed.

.

Noise source measurem't complete

is

15. Turn on the amplier.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

16.

2-34

N

Press

MEASURE EDFA

.

Performing Measurements

Running a Test

17. Wait until the message

18.

19.

20.

21.

Turn

Press

ait

W

Press

the

o

N

N

N

N

N

N

N

N

N

N

N

N

MEASURE

the

until

NN

NN

N

N

N

N

N

N

N

N

N

CALC

EELED

N

N

N

N

NN

N

N

N

NN

NN

GAIN

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

ASE

message

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NF

noise

N

NN

Measure EDFA complete

.

source

.

complete

Measure

ASE

NN

.

is displayed.

displayed.

is

22. After approximately 30 seconds, the gain and noise gure traces are

displayed as shown in the following gure.

2-35

Performing Measurements

Running a Test

2-36

Conguring the Program

This section explains several instrument settings that can be changed from

the Setup menu. Unless you are knowledgeable about measurement theory,it

is best to leave these settings alone|they are already set to optimum values.

The Setup menu allows you to congure the following parameters:



Change the video bandwidth.



Set the ADC trigger delay.



Set the number of video averag for the measurements.

NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN

Use the

default

The

turning

at

N

N

N

N

N

N

N

ADCTRIG

kHz,

25

VID BW

setting

NN

N

N

N

N

N

N

N

N

N

N

N

the

o

the

measurements

.

values

ASE

the

Use

default

averaged

are

gure

accuracy

the

.

N

N

N

N

N

N

N

N

N

N

N

VID

condition

Although

AutoMan

\manual" with

is

N

N

N

N

N

N

N

N

N

N

N

N

N

N

N

NN

NN

NN

DELAY

to

laser

N

N

N

N

is a

N

made

N

N

N

N

N

N

N

On

ADC

N

N

N

N

value

default

are

N

N

NN

N

N

N

AVG

together for

decreasing

noise

the

of

softkey

softkey

allows

measuring

trigger

midway

N

N

N

NN

N

N

N

N

N

softkey

Off

10

of

the three

video

measurements

change

to

a setting

you

ASE.

the

delay

the

in

set

to

which

traces

averaging

the

of 300

specify

to

Because the

set

is

cycle

\o"

video

the

means

used

reduces

aected.

is

video

Hz.

to 10

that

to

bandwidth.

time

the

laser is

This

.

s



which

averaging

values

the

calculate

measurement

the

delay

ensures

results

the

The

from

modulated

average

in

number

ten

of

gain

that

The

.

traces

and

time

noise

,

2-37

Performing Measurements

Conguring the Program

3

Programming

Programming

This chapter documents the programming commands for the EDFA test

personality.EDFA commands can be called from programs in the same

manner as any optical spectrum analyzer command. For information on

building and running programs, refer to the

Spectrum Analyzers Programmer's Guide

HP 71450B/1B/2B Optical

.

Successful programs will follow the following recommended algorithm:

commands

Send

strings

ASCII

Query responses

as

1. Start the personality with the

2. Use

Refer to

Programmer's

Use

3.

spectrum analyzer

the

HP

personality

A

EDF

commands to

71450B/1B/2B Optical

.

Guide

command

edfa_ng

set the

listed

command.

center

wavelength

Spectrum Analyzer

chapter

this

in

to perform

and

a

span.

measurement.

commands

A

EDF

an

HP

used

V

method

The

Using

programming

(and

iooutputs(723L,

Using an

the same

HP 9000

command would

are

ectra

sent

depends

computer

),

C

in

"edfa_ng",

Series

to

on

send

300

be

optical

the

programming

the

the

with

command

a

technical

as

sent

spectrum analyzer

language

HP-IB Interface

follows:

as

7);

computer

with

follows:

as

and environment.

Command

and

ASIC

HP-B

the

Library

language

strings

ASCII

OUTPUT 723;"edfa_ng", 7

Some EDFA commands can be issued as a query. A query causes data to be

returned to the computer from the optical spectrum analyzer. The data is

returned

string

the

syntax

ASCII

an

as

1.550000E-006

diagram

shows

string.

the

example

or

F

representing

query

a

of

form

the

,

1550

response

ngpgpw?

nanometers

.

query might

The

.

return

following

.

,

3-2

Programming

Conguring the Program

Some optical spectrum

analyzer commands are

used

Programming

commands

The following table lists EDFA functions that should be controlled using

optical spectrum analyzer commands. These functions have no equivalent

EDFA programming command. Refer to the

Spectrum Analyzers Programmer's Guide

HP 71450B/1B/2B Optical

for information on these

commands.

Optical Spectrum Analyzer Commands

OSA

EDFA Softkey Denition

Command

ADCTRGDLY ADCTRIG DELAY Delays ADC triggering.

CENTERWL | Sets the center wavelength value.

sweep

sweep

wavelength

wavelength value

wavelength

stop

amplitude

excursion

peak

averaging.

video

commands

indicates

obtain

a

.

mode

span.

.

.

value

.

scale

.

value

.

lter

Some

.

number

the

measurement

entries

value

refer

adjacent

of

.

following tables

The

term

the

smooth

measurement

CONTS CONT

SWEEP

Selects

continuous

SNGLS SINGLE SWEEP Selects single

SP | Sets

ARTWL

ST

OPWL

ST

LG LOG

MKPX PEAK

VG

A

V

VB VID

list

factor

points averaged

VID

the

.

EXCURSN

VG

A

BW

The

| Sets

| Sets

dB/DIV

AutoMan

O

On

programming

smooth

together to

the

the start

the

Changes logarithmic

marker

Sets

on

urns

T

video-bandwidth

Select

facter

.

mode

mathmatically dened by the following equation:

smooth f actor

0:8(trace length)(resolution bandw idth

=

span

)

to

is

It

3-3

Programming

Conguring the Program

Commands by Functional Group

Function Softkey/Function Programming

Command

Starting and Exiting

Starts EDFA test personality. EDFA edfa ng

Exits program. EXIT ngpexit

Menu Selection:

Startup menu. ngpset

Setup menu setup ngpseta

Auto menu

Manual

Return

Return

Exit

Exit

Making

Displa

Zoom

Measure

Measure

Measure

Measure

Measure

Calculate

(ngp=1)

(ngp=0)

menu

auto menu

to

manual

to

results menu.

laser

adjust

Measurements:

adjust

laser

ys

nm

2

to

probe

probe

and

A

EDF

output Nsource

output

gain/nf

. auto ngpae

menu.

procedure

menu.

at laser

span

source

source.

calculate

Nsource

and

.

.

\on".

\o".

extract

.

wavelength.

gain/nf

results.

.

manual ngpme

menu.

prev

menu

prev

DONE ngpsatr

LASER

ADJUST

ZOOM ngpsatb

(auto)

MEASURE

MEASURE

MEASURE

MEASURE

MEASURE

CAL

EELED

(manual)

Nsource

(auto)

A

EDF

(manual)

EDFA

ASE

NF

GAIN

C

ngpa

ngpm

ngprep

ngpsata

ngpx

ngpx

ngpedfa

ngp

ngpz

ngpw

Measure laser/probe source. ngpsrce

Display and Update Data:

Display results. ngpres

Refresh display values. ngpval

values.

displayed

Resets

Refresh

displa

text.

y

ngpvalr

ngpdisp

y

3-4

Programming

Conguring the Program

Commands by Functional Group (continued)

Function Softkey/Function Programming

Command

Measurement Parameters:

Calculate gain/nf raw data. ngpgain

Query Data:

Queries laser wavelength

Queries laser power

Queries gain at marker wl

Queries noise gure at marker wl

peak

Queries wavelength

gain at

Queries

noise

Queries

3dB

Queries

Queries mode:

measurement

Queries

measurement

Queries

measurement

Queries

marker

Queries

rbw

Queries

scale

Queries

smoothing

Queries

at gain

gain

gure

bandwidth

auto

1

wavelength

span

/

factor

factor

peak

gain

at

of

0

,

centerwl

span

video

gain

for

peak

gain

man,

bandwidth

peak

.

curve

2

prog

wl

Laser Wavelngth

Laser Power

Gain ( nm)

NF ( nm)

WL at

Gain

NF

Bandwidth

gain pk

at gain

gain

at

pk

pk

(3dB)

ngpsatw?

ngpsatp?

ngpmkg?

ngpmkn?

ngpgpw?

ngpgpg?

ngpnf?

ngpbw?

ngp?

ngpcwl?

ngpspan?

ngpvb?

ngpmkw?

rbspan?

ngpscale?

smfactor?

3-5

Programming

Conguring the Program

Softkeys versus Commands

Softkey Equivalent

Denition

Programming Command

ADCTRIG DELAY ADCTRGDLY Refer to OSA Programmer's Guide.

ADJUST LASER ngpsata Displays laser adjust menu.

auto ngpae Enter auto menu

(ngp1)

CALCGAINNF ngpw Calculate gain/nf and extract results.

CONT SWEEP CONTS Refer to OSA Programmer's Guide.

DONE ngpsatr Exit adjust laser procedure.

EDFANG edfa ng Starts personality.

auto

help

setup

help

manual

output

output

noise

noise

manual

setup

menu

for

for

A

menu.

.

manu

results.

menu

start.

menu

with

and

with

source

source

menu.

.

help

help

.

help

(ngp0)

noise

calculate

noise

(auto)

.

(manual)

.

.

.

source

gain/nf

source

\o".

.

\on".

EXIT ngpexit Exits

HELP ngphelpa Displa

HELP ngphelpm Displa

HELP ngphelpr Displa

HELP ngphelps Displa

HELP ngphelp Displa

manual ngpme Displa

menu

ASE

A

A

EDF

EELED

Nsource

(auto)

(manual)

ngpz Measure

ngpedfa Measure EDF

y

ngp

Measure

ngpx Measure

ngpx Measure

ngpm Displa

MEASURE

MEASURE EDF

MEASURE

MEASURE

MEASURE

prev

setup ngpseta Displa

personality

ys

ys manual

ys

ys

y

y

y

y

SINGLE SWEEP SNGLS Refer to OSA Programmer's Guide.

VID AVG On O VAVG Refer to OSA Programmer's Guide.

VID BW AutoMan VB Refer to OSA Programmer's Guide.

ZOOM ngpsatb Zoom to 2 nm span at laser wavelength.

3-6

Commands in Alphabetical Order

Programming

Conguring the Program

Programming

Denition Softkey

Command

edfa ng Starts EDFA Noise Gain Prole personality. EDFANG

ngp? Queries mode: 1 auto, 0 man, 2 prog.

ngpa Displays auto menu. prev menu

ngpae Displays auto menu

ngpbw? Queries displayed

(ngp=1)

. auto

Bandwidth (3dB)

value.

ngpcwl? Queries measurement center wavelength.

ngpdisp Refresh display text.

ngpedfa Measure EDF

Aand

calculate gain/nf

.

MEASURE EDF

ngpexit Exits program. EXIT

data.

raw

y

y

y

y

y

ys

gain/nf

displa

displa

help

help

help

help

help

manual

manual

displa

Gain

yed

WL

yed

start.

for

auto

for

manual.

for

results.

for

setup.

for

menu.

menu

Gain

yed

NF ( nm)

at

.

(ngp=0).

at

gain

(

gain

nm)

value.

peak

value

pk

.

value

value

.

.

HELP

HELP

HELP

HELP

HELP

prev menu

manual

ngpgain Calculate

ngpgpg? Queries

ngpgpw? Queries

ngphelp Displa

ngphelpa Displa

ngphelpm Displa

ngphelpr Displa

ngphelps Displa

ngpm Displays

ngpme Displa

ngpmkg? Queries

ngpmkn? Queries displayed

ngpmkw? Queries marker wavelength.

ngpnf? Queries displayed

NF at gain peak

value.

ngprep Exit results to measurement menu.

ngpres Display results.

menu.

adjust

laser

ngpsata Displa

ngpsatb Zoom

ngpsatp? Queries displa

ys

wavelength.

laser

at

span

nm

2

to

yed

Laser Power

value.

ADJUST

ZOOM

LASER

A

(auto)

3-7

Programming

Conguring the Program

Commands in Alphabetical Order (continued)

Programming

Denition Softkey

Command

ngpsatr Exit adjust laser procedure. DONE

ngpsatw? Queries displayed

Laser Wavelngth

value.

ngpscale? Queries scale factor for gain peak wavelength.

ngpset Dispay startup menu.

ngpseta Display setup menu. setup

ngpspan? Queries measurement span.

ngpsrce Measure laser/probe source.

values.

y

ngpval Refresh

ngpvalr Resets

ngpvb? Queries

ngpw Calculate

ngpx Measure

displa

displayed

measurement

gain/nf

source

probe

values.

video

and extract

.

bandwidth.

results.

CAL

MEASURE

MEASURE

ngp

y

Measure

output

Nsource

MEASURE

\on".

(manual)

\o".

Nsource

ngpz Measure

rbspan? Queries

smfactor? Queries

output

span.

/

rbw

smoothing

factor

MEASURE

.

GAIN NF

C

EELED

Nsource

A

EDF

ASE

and

3-8

4

Reference

Reference

Chapter Contents

Menu Map

Error Messages

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

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

Measurement Calculations

Gain and Noise Figure Traces

Laser Wavelngth and Power

WL at gain peak

gain

at

Gain

gain

at

NF

Bandwidth

Characteristic

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

:

:

:

:

peak

::

::

(3dB)

::

:

::

::

:

peak

Measurement

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

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

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

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

::

::

::

::

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

::

::

::

::

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

:

::

::

:

:

:

:

::

::

:

:

:

:

:

:

:

:

:

Uncertainty

:

4-3

4-4

4-5

4-5

4-6

4-6

4-7

:

:

:

:

:

4-7

:

:

:

:

:

4-7

:

:

:

:

:

4-8

:

:

:

:

:

:

4-2

Menu Map

4-3

error 111

Error Messages

This section denes error messages for the EDFA test personality. Error

messages not dened in this section originate with the HP 70950B/1B/2B

module and are documented in the

Analyzers Reference

.

HP 71450B/1B/2B Optical Spectrum

Error messages can result from incorrect operating procedures, illegal

programming commands, or hardware failures. Normally, the optical

spectrum analyzer removes error messages from the screen as soon as the

messages

error

conditions

error

can be

retrieved via

HP 71450B/1B/2B

the

Memory

perform

,

objects

menus

in

to

on

Error:

and

,

the

learn

of

information

EDFA

memory

Erase



user

memory

Guide

corrected.

are

HP-IB by

Optical Spectrum

command.

ERR?

program

The

following:

the

following

the

downloadable

71450B/1B/2B

HP

erase

to

how

have

you

If

executing the

Analyzers Programmer's

run

has

from

types

programs

Optical

objects

these

computer

a

ERR?

out

memory: saved

Refer

.

Spectrum

.

,

command.

free

of

to the

Analyzers

Refer

memory

traces

chapter

Guide

T

.

,

on

User's

the

to

for

free

o

limit

managing

lines

,

error 112

error 116

in

positive

than

<

zero

Noise

EDFA

calculation

.

values

Figure

less

EDFA Command Error:

Error:

0

.V

Invalid

alid noise

data

gure results

are always

resulted

has

An unrecognized argument has been used with

gure

noise

a

the programming command. Refer to Chapter 3 for the correct use of the

command.

4-4

Measurement Calculations

The following calculations describe the process for obtaining the resultant

traces for gain and noise gure, as well as each measurement result shown at

the top of the display. A special

typeface

is used in this chapter to indicate

displayed quantities.For example when the laser wavelength is referenced, it

is printed as

Laser Wavelngth

.

Gain

The

traces

(

(

measur

ace C

tr

tr

ace

ace A

tr

B

All

for

wavelength,

Smoothingf actor

and

Gain and

Noise

Noise

Figure

Figure

as follows:

)

measur

ement

ement

(

measur

)=(G)

three traces

=

ement

converted

are

ASE

(

N)+

resolution bandwidth

a value

for gain

G=gain

NF

=

Gain(display

(

F

N

=

greatest odd integ er

displ

ay

traces

E

=

AS

)

N

=

variation

is

=

ASE

hvGain

)

ed

=

)

ed

=

Traces

calculated

are

output

A

F

D

A

F

D

E

=

E

sour

noise

=

to

dBm

from

wavelength)

with

calculated

(

)

A

0

B

C

1

+

Gain

smoothed

smoothed

Gain

NF



0:83T r ace length

(

noise

output

spectr

ce

watts

as:

from

source

(

noise

um

(oating

F

3

three

the

of

sour

point

each

or

Res B W

Span

measurement

)

f

)

on

ce

and

point,

trace



corrected

4-5

Reference

Measurement Calculations

Laser Wavelngth and Power

The laser power and wavelength determine the saturation condition for

the EDFA. The Noise Gain Prole routine measures and records the laser

wavelength and power level referenced to the input of the EDFA. Since

the laser is modulated, the desired power level is the average power of the

source. The OSA measures the average power and wavelength accurately

by ZOOMing in on the signal. This allows more measurement time on the

signal to enhance the measurement repeatability. From the ZOOMed trace,

the power and wavelength are extracted using the following calculations.

moothing

S

l

actor

f

at

WL

exact

The

algorithm

aser

l

W

aser

eatest

r

g

=

gain

wavelength

:

W

P

=

L

peak

R

peak

odd

=

peak

(

doubl

integer

calculated

is

(

smoothed

smoothed

e



8

:

0

for

3

T

the

r

tr

ace

ace

gain

tr

)

ace

eng

l

)

th

peak

R

3

using

es

S

B

pan

W

the



following

The gain and noise gure calculations return traces in an unsmoothed form.

Before the traces are displayed, the gain trace is expanded to enhance the

amplitude resolution.

1. The trace maximum gain value is determined.

10.

trace

The

2.

The expanded

3.

multiplied

is

trace

by

smoothed

is

325/max gain

the

and

up

new

maximum

a

to

maximum

of

point

is

determined.

4. The

wavelength of the maximum point is recorded as wavelength at gain

peak.

5. The smoothed trace is un-scaled and displayed as the gain trace

4-6

.

Reference

Measurement Calculations

Gain at gain peak

The gain at gain peak is the gain value from the displayed gain trace at the

wavelength at gain peak.

NF at gain peak

gain

NF at

The

peak.

gain

Bandwidth

bandwidth

The

marker

between

side

bandwidth

.

the

gain

peak

(3dB)

(3dB)

function

trace

value

the

is

is calculated

value

set

points which

to

of

0

noise

the

3dB.

are 3dB

gure

from the

the

is

It

down

at

trace

peak

gain

wavelength

the

from

wavelengh

the

the

using

dierence

on

peak

A

OS

either

at

4-7

Characteristic Measurement Uncertainty

This section is a guide for understanding the various sources of measurement

uncertainty for

EDFA Gain

and

Noise Fig

ure. The actual uncertainty

depends on the equipment you are using. This section takes the conservative

approach of treating all of the individual measurement uncertainties as

systematic, that is, uniform probability distribution within the specied limits.

The uncertainty calculations assume the following points:



An HP 71452B optical spectrum analyzer is used.

1562

source

loss

source

polarization

nm.

.

and

amplitude

accuracy

wavelength

or

the

in

This optical

1542 to

uncertainty values

The



source is

The



Good



maintained

mismatch

optical

The



optical

an

optical

The



with

reference

total

All



1562 nm.

quality

to

uncertainty

spectrum

power

spectrum

the

either

.

uncertainties

spectrum analyzer

apply from

have

8168B/C

contact

dB

35

minimum

an HP

physical

.

analyzer

with

meter

analyzer

8168B/C

HP

calculated

are

uncertainty

=2

has improved

tunable

ber

has

dB

0.1

6

has

tunable

r

X

1542

laser

optic

return

been

absolute

been

laser

as

2

U

3

to

connectors

recently

recently

shown

where \U" is the uncertainty of each individual contributor.

used

are

dB

0.25

.

another

following

sensitivity

and

maximum

calibrated

calibrated

wavelength

equation:

from

using

4-8

Characteristic Measurement Uncertainty

Uncertainties

With Splices1With Connectors

Gain Uncertainty

Noise Figure Uncertainty

Gain Shape Uncertainty

1

Assumes 0.05 dB uncertainty for each splice.

2

Assumes 0.25 dB uncertainty for each connector.

3

Calculated for 5.5 dB ratio for EELED ON and EELED OFF at output of EDFA.

3

0.11 dB 0.30 dB

3

0.34 dB 0.53 dB

3

0.10 dB 0.10 dB

Reference

2

4-9

Reference

Characteristic Measurement Uncertainty

Index

Index

111 EDFA Memory Error, 4-4

1

112 EDFA Noise Figure<0 Error, 4-4

116 EDFA Command Error, 4-4

2011 Memory overow error, 1-7

2

2053 Storage device error, 1-5

3

3

accuracy

A

ADCTRIG

ADJUST

bandwidth,

B

battery

CAL

C

calculations,

calibration,

command

congure,

connectors

CONT

bandwidth,

dB

,optical

ALL

SWEEP

,

4-7

softkey,

Y

v

ensuring,

DELA

LASER softkey,

4-7

dB,

3

spectrum

2-12

softkey,

4-5

2-3

3-2

syntax,

2-37

, cleaning,

v

,

related programming command, 3-3

disk drive

D

addressing, 1-6

installing from, 1-6

1-6

type,

DISPLAY

key,

vi

2-37

2-33

analyzer,

2-22

1-2

Index-2

EDFA NG softkey, v

E

equations

uncertainty, 4-8

error messages, 4-4

111 EDFA Memory Error, 4-4

112 EDFA Noise Figure<0 Error, 4-4

116 EDFA Command Error, 4-4

2011 Memory overow, 1-7

2053 Storage device error, 1-5

gure traces, gain and noise, 4-5

F

fusion splices, v

gain at

G

gain

gain

HPIB

H

HP-LIF

installation,

I

laser

L

license

gain peak,

gure

peak

4-7

gain,

4-7

NF,

wavelength,

DISK

format

3.5-inch

a

from

the

from

power and

,

agreement, vii

4-7

4-5

trace,

4-6

softkey,

diskette,

1-2

diskette

memory

wavelength, 4-6

1-6

card,

LOG dB/DIV

related programming command, 3-3

measurement

M

accuracy, v

calculations, 4-5

card,

4-8

softkey,

1-2

uncertainty,

MEASURE Nsource

memory

MENU key, vi

menu map, 4-3

messages.

See

error messages

1-2

drive,

1-4

2-34

1-6

Index-3

NF at gain peak, 4-7

N

noise gure trace, 4-5

optical isolator, using, v

O

optical spectrum analyzer

battery, 1-2

POWER FOR CAL softkey, 2-12, 2-22

P

power, laser, 4-6

programming commands, 3-2

ERR?, 4-4

syntax, 3-2

versus softkeys, 3-6

query responses,

Q

regulatory

R

remote

SINGLE

S

related

commands.

SWEEP

3-2

information,

programming

softkeys

4-3

map,

programming

versus

test

T

running, 2-23

diagram ,

timing

iii

trigger,

2-25

tunable laser source, iii

tunable source, iii

uncertainty

U

connector, v

equation,

gain

integrated ASE

4-8

measurements,

measurements,

noise gure measurements, 4-9

upgrade kit, iv

USER key, v, vi

ii

programming

See

command,

commands,

4-9

commands

3-3

3-6

4-9

Index-4

VID AVG On O softkey, 2-37

V

VID BWAutoMan softkey, 2-37

warranty, x

W

WAVELEN FOR CAL softkey, 2-12, 2-22

wavelength at gain peak, 4-6

wavelength, laser, 4-6

Index-5