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User's Guide
HP 8504B Precision
Re ectometer
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
merchantability and tness for a particular purpose. Hewlett-Packard shall
not be liable for errors contained herein or for incidental or consequential
damages in connection with the furnishing, performance, or use of this
material.
Restricted Rights Legend. Use, duplication, or disclosure by the U.S.
Government is subject to restrictions as set forth in subparagraph (c) (1) (ii)
of the Rights in Technical Data and Computer Software clause at DFARS
252.227-7013 for DOD agencies, and subparagraphs (c) (1) and (c) (2) of the
Commercial Computer Software Restricted Rights clause at FAR 52.227-19 for
other agencies.
Copyright Hewlett-Packard Company 1992, 1993, 1994, 1995
c
All Rights Reserved. Reproduction, adaptation, or translation without prior
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 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.
WARNING No operator serviceable parts inside. Refer servicing to quali ed
personnel. To prevent electrical shock and LED radiation, do not remove
covers.
CAUTION Before switching on this product, make sure that the line-voltage selector
switch is set to the voltage of the power supply and the correct fuse is
installed. Assure the supply voltage is in the speci ed range.
CAUTION Electrostatic discharge (ESD) can damage circuits associated with rear-panel
connectors. Therefore, before connecting any cable to a rear-panel connector,
momentarily short the center and outer conductors of the cable together.
Avoid touching the rear-panel connectors without rst touching the frame of
the instrument. Be sure that the instrument is properly earth-grounded to
prevent buildup of static charge.
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.
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 of passive ber-optic devices such as couplers, attenuators,
connectors, and isolators.
High-resolution measurements of lightwave path discontinuities based on a
known refractive index.
Measurement of refractive index of material based on a known distance
between two discontinuities.
High-resolution measurement of path length, expressed as transit time.
Measurements of bulk optic devices such as lenses, AR coatings, and
crystals.
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 The precision re ectometer provides guided setup and guided calibration
reduce measurement procedures that help you prepare the instrument for measurements.
time These procedures consist of a series of screens that present step-by-step
instructions.
Procedure Task
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.
Refer to Chapter 2 for a complete explaination of guided setups and guided
calibrations.
You should calibrate the instrument:
After the instrument has warmed up for 1 hour.
Before making any measurements.
Front-panel adapters The precision re ectometer's three front-panel connectors are compatible
can be changed with 9/125 m ber-optic cables. All three connectors are adapters that can
be easily changed or removed for cleaning. Simply unscrew each adapter
in a counterclockwise direction. Useful measurements are achievable with
other adapters, but measurement performance may not be optimum. Refer
to \Front-Panel Fiber-Optic Adapters" in Chapter 5 for a complete listing of
available adapter types.
Softkeys select Many instrument features are available through the use of softkeys. Softkeys
instrument features 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 dierent 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.
ext Waiting for an external trigger at the rear panel.
Hld Hold sweep.
OVL Amplitude of re ected signal at test port is too large.
vii
front-panel knob Allows continuous adjustments to current values for
various functions such as start value, scale, and others.
Values changed by the knob are eective immediately, and
require no units terminator.
4G/n5 Terminates numeric keypad entries with 106 multiplier.
9
4M/5 Terminates numeric keypad entries with 106 multiplier.
6
4K/m5 Terminates numeric keypad entries with 106 multiplier.
3
4x15 Terminates unitless entries such as averaging factors.
4ENTRY OFF5 Disables the keypad, knob, and step keys until another
function is selected.
viii
Keys in this manual
4boxed5 letters indicate normal front-panel keys. Most of these functions also can be performed using
softkeys.
NNNNNNNNNNNNNNNNNNNN
shadow letters indicate softkeys.
ix
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.
CAUTION 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.
WARNING The warning sign denotes a life-threatening hazard. It calls attention to a
procedure which, if not correctly performed or adhered to, could result
in injury or loss of life. Do not proceed beyond a warning sign until the
indicated conditions are fully understood and met.
L
Instruction The instruction manual symbol. The product is marked with this symbol when it is
Manual necessary for the user to refer to the instructions in the manual.
j The line-power on symbol.
The line-power o symbol.
CE The CE mark is a registered trademark of the European Community. (If accompanied by a
year, it is when the design was proven.)
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
are available for Hewlett-Packard products.
For any assistance, contact your nearest Hewlett-Packard Sales and Service
Oce.
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
the product to Buyer. However, Buyer shall pay all shipping charges, duties,
and taxes for products returned to Hewlett-Packard from another country.
Hewlett-Packard warrants that its software and rmware designated by
Hewlett-Packard for use with an instrument will execute its programming
instructions when properly installed on that instrument. Hewlett-Packard
does not warrant that the operation of the instrument, or software, or
rmware will be uninterrupted or error-free. Limitation of Warranty
The foregoing warranty shall not apply to defects resulting from improper
or inadequate maintenance by Buyer, Buyer-supplied software or
interfacing, unauthorized modi cation or misuse, operation outside of the
environmental speci cations for the product, or improper site preparation
or maintenance.
NO OTHER WARRANTY IS EXPRESSED OR IMPLIED. HEWLETT-PACKARD
SPECIFICALLY DISCLAIMS THE IMPLIED WARRANTIES OF
MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE.
Exclusive Remedies
THE REMEDIES PROVIDED HEREIN ARE BUYER'S SOLE AND EXCLUSIVE
REMEDIES. HEWLETT-PACKARD SHALL NOT BE LIABLE FOR ANY
DIRECT, INDIRECT, SPECIAL, INCIDENTAL, OR CONSEQUENTIAL
DAMAGES, WHETHER BASED ON CONTRACT, TORT, OR ANY OTHER
LEGAL THEORY.
xii
Contents
1. Installing
Step 1. Inspect the shipment . . . . . . . . . . . . . 1-4
Step 2. Connect the two instrument sections . . . . . . 1-6
Step 3. Set the line voltage . . . . . . . . . . . . . . 1-8
Step 4. Connect the rear-panel cables . . . . . . . . . 1-11
Step 5. Verify Operation . . . . . . . . . . . . . . . 1-12
To replace the line fuse . . . . . . . . . . . . . . . . 1-20
Cleaning Connections for Accurate Measurements . . . . 1-22
To clean a non-lensed connector . . . . . . . . . . . 1-24
To clean an adapter . . . . . . . . . . . . . . . . 1-25
To test insertion loss . . . . . . . . . . . . . . . . 1-25
To test return loss . . . . . . . . . . . . . . . . . 1-26
Returning Your Instrument . . . . . . . . . . . . . . 1-27
To return the instrument for service . . . . . . . . . 1-28
2. Performing Guided Setups and Calibrations
Running Guided Setups and Calibrations . . . . . . . . 2-6
To perform a guided setup (devices with pigtail) . . . 2-7
To perform a guided setup (devices without pigtail) . . 2-13
To perform a guided calibration . . . . . . . . . . . 2-18
Performing Manual Calibrations . . . . . . . . . . . . 2-20
To balance the receiver . . . . . . . . . . . . . . . 2-23
To calibrate the magnitude . . . . . . . . . . . . . 2-25
To calibrate for an external source . . . . . . . . . . 2-26
To turn o calibration data . . . . . . . . . . . . . 2-28
To enter the standard's re ection percentage . . . . . 2-28
To turn chromatic dispersion correction on and o . . . 2-28
To use the Option 001 cable tray . . . . . . . . . . 2-29
3. Performing Measurements
Setting the Measurement Range . . . . . . . . . . . . 3-4
To select the source wavelength . . . . . . . . . . . 3-6
To automatically tune to a response . . . . . . . . . 3-7
To change the displayed scale . . . . . . . . . . . . 3-7
To change the refractive index . . . . . . . . . . . 3-8
Reducing Displayed Noise . . . . . . . . . . . . . . 3-9
Contents-1
To reduce the displayed noise . . . . . . . . . . . . 3-11
Using Markers . . . . . . . . . . . . . . . . . . . . . 3-12
To display a peak response . . . . . . . . . . . . . 3-16
To change the measurement range . . . . . . . . . . 3-16
To make relative measurements . . . . . . . . . . . 3-16
To position a xed reference marker . . . . . . . . . 3-17
To change the peak de nition . . . . . . . . . . . . 3-17
To turn markers o . . . . . . . . . . . . . . . . 3-18
Creating Limit Lines . . . . . . . . . . . . . . . . . 3-19
To enter limit-line segments . . . . . . . . . . . . . 3-23
To display or hide limit lines . . . . . . . . . . . . 3-23
To turn on limit testing . . . . . . . . . . . . . . 3-24
Tutorial: Using Limit Lines . . . . . . . . . . . . . 3-25
Storing Traces to Memory . . . . . . . . . . . . . . 3-34
To view memory traces . . . . . . . . . . . . . . . 3-35
Saving Instrument States to Registers . . . . . . . . . 3-36
To save to a register . . . . . . . . . . . . . . . . 3-38
To recall a register . . . . . . . . . . . . . . . . . 3-38
To increase user memory . . . . . . . . . . . . . . 3-39
Saving Instrument States to Files . . . . . . . . . . . 3-40
To save to a disk . . . . . . . . . . . . . . . . . 3-41
To change a le name . . . . . . . . . . . . . . . 3-42
To recall an external le . . . . . . . . . . . . . . 3-43
To delete an external le . . . . . . . . . . . . . . 3-43
To format an external disk . . . . . . . . . . . . . 3-43
To connect a disk drive . . . . . . . . . . . . . . . 3-44
Changing Colors and Audible Warnings . . . . . . . . 3-45
To adjust displayed colors . . . . . . . . . . . . . 3-45
To turn on the warning beep . . . . . . . . . . . . 3-45
To turn o the \done" beep . . . . . . . . . . . . 3-46
Printing and Plotting . . . . . . . . . . . . . . . . 3-47
To print the display . . . . . . . . . . . . . . . . 3-48
To plot the display . . . . . . . . . . . . . . . . 3-48
To print or plot measurement and parameter values . . 3-49
To enter the printer/plotter type and address . . . . . 3-49
To abort a print or plot . . . . . . . . . . . . . . 3-50
Contents-2
4. Programming
Controlling the Instrument . . . . . . . . . . . . . . 4-4
To select the HP-IB mode . . . . . . . . . . . . . 4-8
To change the HP-IB address . . . . . . . . . . . . 4-8
Monitoring the Instrument . . . . . . . . . . . . . . 4-9
IEEE 488.2 Common Commands . . . . . . . . . . . . . 4-12
Instrument Commands . . . . . . . . . . . . . . . . 4-15
Keys versus Commands . . . . . . . . . . . . . . . 4-54
5. Reference
Menu Maps . . . . . . . . . . . . . . . . . . . . . 5-3
Keys, Softkeys, and Connectors . . . . . . . . . . . . 5-11
Block Diagram . . . . . . . . . . . . . . . . . . . 5-53
Front-Panel Fiber-Optic Adapters . . . . . . . . . . . 5-54
Part Numbers . . . . . . . . . . . . . . . . . . . . 5-55
Instrument Options . . . . . . . . . . . . . . . . . 5-56
Line-Power Cables . . . . . . . . . . . . . . . . . . 5-57
6. Speci cations and Regulatory Information
Speci cations . . . . . . . . . . . . . . . . . . . . 6-4
LED Classi cation . . . . . . . . . . . . . . . . . 6-4
Return Loss Measurement Range . . . . . . . . . . 6-5
Return Loss Uncertainty . . . . . . . . . . . . . . 6-6
Sweep-to-Sweep Repeatability . . . . . . . . . . . . 6-8
Two-Event Spatial Accuracy . . . . . . . . . . . . 6-9
Two-Event Spatial Resolution . . . . . . . . . . . . 6-10
Spurious Responses . . . . . . . . . . . . . . . . 6-12
Characteristics . . . . . . . . . . . . . . . . . . . 6-14
Regulatory Information . . . . . . . . . . . . . . . 6-16
Notice for Germany: Noise Declaration . . . . . . . . 6-16
7. Error Messages
Message De nitions . . . . . . . . . . . . . . . . . 7-3
Error Message Numbers . . . . . . . . . . . . . . . 7-11
Index
Contents-3
Contents
1
Installing
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. It is
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.
WARNING For continued protection against re hazard, replace line fuse only with
same type and ratings. The use of other fuses or materials is prohibited.
The correct fuse types are listed on the rear panel of each instrument
section.
WARNING If this product is to be energized via an external autotransformer for
voltage reduction, make sure that its common terminal is connected to a
neutral (earthed pole) of the power supply.
CAUTION When installing the product in a cabinet, the convection into and out of
the product must not be restricted. The ambient temperature (outside
the cabinet) must be less than the maximum operating temperature of
the product by 4 C for every 100 watts dissipated in the cabinet. If the
total power dissipated in the cabinet is greater than 800 watts, then forced
convection must be used.
CAUTION 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 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-4
Step 2. Connect the two instrument sections : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-6
Step 3. Set the line voltage : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-8
Step 4. Connect the rear-panel cables : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-11
Step 5. Verify Operation : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-12
To replace the line fuse : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-20
Cleaning Connections for Accurate Measurements : : : : : : : : : : : : : : : : : : : : : 1-22
To clean a non-lensed connector : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-24
To clean an adapter : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-25
To test insertion loss : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-25
To test return loss : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-26
Returning Your Instrument : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 1-27
To return the instrument for service : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 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 oce. HP will arrange for repair or replacement of
damaged or incomplete shipments without waiting for a settlement from
the transportation company. Notify the HP customer engineer of any
problems.
1-4
Installing
Step 1. Inspect the shipment
Precision Re ectometer Accessories
Item Quantity
Standard:
Wood box 1
100 cm FC/PC ber-optic cable 2
Fiber-optic cable adapter1 1
Low-re ection termination 1
Isopropyl alcohol cleaner (30 ml) 1
Cotton swabs 1
Tape measure (3 m) 1
Rear-panel BNC cable 1
Rear-panel IO INTERCONNECT cable 1
Rear-panel line-power cable 1
Option 001 Accessory Kit:
Cable tray 1
Fiber-optic cable adapter1 1
40 cm FC/PC ber-optic cable 2
50 cm FC/PC ber-optic cable 2
75 cm FC/PC ber-optic cable 2
125 cm FC/PC ber-optic cable 2
150 cm FC/PC ber-optic cable 2
175 cm FC/PC ber-optic cable 2
1 Used to connect two FC/PC ber-optic cables.
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.
2. Place the lightwave section on a steady, sturdy work surface.
3. Place the display processor on top of the lightwave section so that the
front edge of the display processor is about 0.6 cm (0.25 in) in front of the
lightwave section.
4. Slightly lift the rear of the display processor and slide it back until its front
edge is even with the front edge of the lightwave section.
1-6
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.
1. Determine the line voltage of the AC power source. The line-power cords
should not be connected to the precision re ectometer at this time.
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. See the following gure.
1-8
Installing
Step 3. Set the line voltage
4. Verify that the value of the line-voltage fuse in the pull-out drawer is
correct. 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.
5. 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
1-9
Installing
Step 3. Set the line voltage
CAUTION Do not attempt to rotate the voltage selector cam while it is installed in
the line module or non-repairable damage will result. The cam must be
completely removed from the line module, rotated to the proper position, and
reinstalled.
6. Remove the voltage selector cam from the line module.
7. Rotate the voltage selector cam to the desired 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.
The recommended fuse for 100V and 120V operation is a F1.5A, 250V,
HP part number 2110-0043. The recommended fuse for 220V and 240V
operation is a F0.75A, 250V, HP part number 2110-0063.
10. Close the line-module cover door.
1-10
Step 4. Connect the rear-panel cables
WARNING 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.
CAUTION Always use the three-prong AC power cord supplied with this instrument.
Failure to ensure adequate earth grounding by not using this cord may cause
instrument damage.
1. Connect the I/O interconnect cable between the display processor and the
lightwave section.
2. Connect the BNC cable between the display processor and the lightwave
section.
3. Connect the power cable to display processor and the lightwave section.
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 properly
Over-tightening or under-tightening connectors can result in misalignment and nonrepeatable
measurements. Always nger tighten connectors in a consistent manner. Refer to the manufacturer's
data sheet for any torque recommendations.
1. Turn the precision re ectometer on, and allow it to warm up for at least
one hour.
2. Clean all cable connectors and front-panel optical ports.
Refer to \Cleaning Connections for Accurate Measurements" for
information on cleaning connectors.
3. Attach one of the 100 cm ber-optic cables to the front-panel TEST PORT
connector.
When mating Super PC connectors, check to see that the keyways on
the Super PC cable connectors are inserted into the slots on the mating
connectors.
4. If there is a protective cap on the free end of the ber-optic cable, remove
it.
5. Attach the other 100 cm ber-optic cable between the front-panel
REFERENCE EXTENSION connectors A and B.
1-12
Installing
Step 5. Verify Operation
The REFERENCE EXTENSION and TEST PORT ber-optic cables must be
equal in length in order for re ections to be viewed on the display.
6. Press 4PRESET5.
The wavelength defaults to 1300 nm.
NOTE
Do not move the reference extension cable for the rest of this procedure. Any movement of this cable
will change the reference signal polarization and will invalidate the calibration.
1-13
Installing
Step 5. Verify Operation
7. Press 4CAL5 and then GUIDED CAL .
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
8. Use the supplied adapter to connect the low-re ection termination to the
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. Adjust the two front-panel REFERENCE POLARIZATION BALANCE knobs
until the line is in the shaded area. See the following gure.
10. Press DONE .
NNNNNNNNNNNNNN
11. Disconnect the low-re ection termination from the ber-optic cable.
12. Press FRESNEL and then MEASURE STANDARD .
NNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
The end of the cable is providing a Fresnel standard.
13. Wait until the asterisk on the display's left-hand side disappears and the
letter C remains 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?
Fresnel response.
15. Press 4MKR FCTN5, MAX SEARCH , and then MKR ZOOM .
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNN
This expands the display around the Fresnel response. Wait for the
response to move to the center of the display.
16. Press MAX SEARCH , and read the marker's amplitude value on the
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
display. If the value is not within the values shown below, thoroughly
clean all connectors on the cables and front panel, and repeat this
procedure from step 1.
Peak value (1300 nm source) : : : : : : : : : : : : : : : : : : : : : : : : : : 015 dB 60.5 dB
Peak value (1550 nm source) : : : : : : : : : : : : : : : : : : : : : : : : 014.7 dB 60.5 dB
1-15
Installing
Step 5. Verify Operation
Marker showing peak value with 1300 nm source.
17. Connect a coupling adapter to the end of the TEST PORT ber-optic cable.
1-16
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 MKR ZOOM as you slowly insert the connector into the
NNNNNNNNNNNNNNNNNNNNNNNNNN
adapter until the span is 1 mm. The Fresnel response should be as close
to the original response as possible and can still be resolved. See the
following gure.
1-17
Installing
Step 5. Verify Operation
Two responses viewed as a single signal.
20. Press 4MEAS5 and then TRIGGER:HOLD to freeze the trace.
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
21. Press 4MKR FCTN5, MAX SEARCH , and then MARKER ! FIXED MKR to
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
turn on the delta marker and to reference the xed marker to zero on one
of the peaks.
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 : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 0.025 mm
1550 nm source : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 0.25 mm
1-18
Installing
Step 5. Verify Operation
Delta marker showing spatial resolution.
24. Press 4PRESET5.
25. Press 4MENU5 and then 1550 nm .
NNNNNNNNNNNNNNNNNNNNNNN
26. Remove the coupling adapter from the ber-optic cable, and repeat this
procedure from step 7 to check the operation at 1550 nm.
1-19
To replace the line fuse
To change the fuse on the display processor section:
1. Disconnect the line-power cord from the display processor section.
2. Use a small at-blade screwdriver to open the pull-out fuse drawer as
shown in the following gure.
1-20
Installing
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.
3. Pull out the fuse drawer. The following list shows the recommended
fuse:
100V and 120V operation : : : : : : : : : : : : F1.5A 250V (HP p/n 2110-0043)
220V and 240V operation : : : : : : : : : : : 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.
Use care in handling all ber-optic connectors.
When inserting a ber-optic connector into a front-panel adapter, make
sure that the ber end does not touch the outside of the mating connector
or adapter.
Because of the small size of cores used in optical bers, care must be used to
ensure good connections. Poor connections result from core misalignment, air
gaps, damaged ber ends, contamination, and improper use and removal of
index-matching compounds.
Use dry connections. Dry connectors are easier to clean and to keep clean.
Dry connections can be used with physically contacting connectors (for
example, Diamond HMS-10/HP, FC/PC, DIN, and ST). If a dry connection
has 40 dB return loss or better, making a wet connection will probably not
improve (and can degrade) performance.
CAUTION Hewlett-Packard strongly recommends that index matching compounds NOT
be applied to their instruments and accessories. Some compounds, such as
gels, may be dicult 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
1-22
Installing
Cleaning Connections for Accurate Measurements
Dust Caps Provided with Lightwave Instruments
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
Inspecting Fiber-Optic Consistent measurements with your lightwave equipment are a good
Cables indication that you have good connections. However, you may wish to know
the insertion loss and/or return loss of your lightwave cables or accessories. If
you test your cables and accessories for insertion loss and return loss upon
receipt, and retain the measured data for comparison, you will be able to tell
in the future if any degradation has occurred.
Connector (or insertion) loss is one important performance characteristic of a
lightwave connector. Typical values are less than 1 dB of loss, and sometimes
as little as 0.1 dB of loss with high performance connectors. Return loss
is another important factor. It is a measure of re ection: the less re ection
the better (the larger the return loss, the smaller the re ection). The best
physically contacting connectors have return losses better than 50 dB,
although 30 to 40 dB is more common.
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, or dents in the metal as well as any other imperfections. Inspect the ber for cracks and chips.
Visible imperfections not touching the ber core may not aect performance (unless the imperfections
keep the bers from contacting).
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.
3. Apply isopropyl alcohol to a new clean lint-free cotton swab or lens paper.
4. Clean the ber end with the swab or lens paper. Move the swab or lens
paper back and forth across the ber end several times.
Some amount of wiping or mild scrubbing of the ber end can help
remove particles when application of alcohol alone will not remove
them. This technique can remove or displace particles smaller than one
micron.
5. Immediately dry the ber end with a clean, dry, lint-free cotton swab or
lens paper.
6. Blow across the connector end face from a distance of 6 to 8 inches using
ltered, dry, compressed air. Aim the compressed gas at a shallow angle to
the ber end face.
Nitrogen gas or compressed dust remover can also be used.
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 air canister.
7. As soon as the connector is dry, connect or cover it for later use.
1-24
Installing
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.
2. Clean the adapter with the foam swab.
3. Dry the inside of the adapter with a clean, dry, foam swab.
4. Blow through the adapter using ltered, dry, compressed air.
Nitrogen gas or compressed dust remover can also be used.
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 air canister.
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:
HP 71450A or HP 71451A optical spectrum analyzers with Option 002
built-in white light source.
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
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
HP 8153 lightwave multimeter with a source and power sensor module in
conjunction with a lightwave coupler
HP 81554SM dual source and HP 81534A return loss module
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 oces 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 cushion the instrument, do not prevent all instrument movement,
and can generate static electricity.
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:
a. Wrap the instrument in anti-static plastic to reduce the possibility of
ESD damage.
b. For instruments that weigh less than 54 kg (120 lb), use a
double-walled, corrugated cardboard carton of 159 kg (350 lb) test
strength. The carton must be both large enough and strong enough to
accommodate the instrument. Allow at least three to four inches on all
sides of the instrument for packing material.
c. Surround the equipment with three to four inches of packing material
to protect the module and to prevent movement in the carton. If
packing foam is not available, the best alternative is S.D.-240 Air Cap
TM
from Sealed Air Corporation, Hayward, California 94545. Air Cap is
plastic sheeting lled with 1-1/4 inch air bubbles. Use pink anti-static
Air Cap. Wrapping the instrument several times in this material should
provide sucient protection and also prevent movement in the carton.
3. Seal the carton with strong nylon adhesive tape.
4. Mark the carton FRAGILE, HANDLE WITH CARE.
5. Retain copies of all shipping papers.
1-28
Installing
Returning Your Instrument
Service Repair Form
Date:
Company:
Address:
Technical contact person:
Phone:
Model number:
Serial number:
P.O. number:
Accessories returned with unit: none cables(s) power cable adapter(s)
Other:
Service Needed: calibration only repair repair and calibration
Other:
Failure symptoms and special control settings:
If unit is part of system, list model number(s) of other interconnected instruments:
1-29
Installing
Returning Your Instrument
Hewlett-Packard Sales and Service Oces
U.S. FIELD OPERATIONS
Headquarters California, Northern California, Southern
Hewlett-Packard Company Hewlett-Packard Company Hewlett-Packard Company
19320 Pruneridge Avenue 301 East Evelyn 1421 South Manhatten Ave.
Cupertino, CA 95014 U.S.A. Mountain View, CA 94041 Fullerton, CA 92631
(800) 752-0900 (415) 694-2000 (714) 999-6700
Colorado Georgia Illinois
Hewlett-Packard Company Hewlett-Packard Company Hewlett-Packard Company
24 Inverness Place, East 2000 South Park Place 5201 Tollview Drive
Englewood, CO 80112 Atlanta, GA 30339 Rolling Meadows, IL 60008
(303) 649-5000 (404) 955-1500 (708) 342-2000
New Jersey Texas
Hewlett-Packard Company Hewlett-Packard Company
120 West Century Road 930 East Campbell Road
Paramus, NJ 07653 Richardson, TX 75081
(201) 586-5400 (214) 231-6101
EUROPEAN FIELD OPERATIONS
Headquarters France Germany
Hewlett-Packard S.A. Hewlett-Packard France Hewlett-Packard GmbH
150, Route du Nant-d'Avril 1 Avenue Du Canada Hewlett-Packard Strasse
1217 Meyrin 2/Geneva Zone D'Activite De Courtaboeuf 61352 Bad Homburg
Switzerland F-91947 Les Ulis Cedex Germany
(41 22) 780.8111 France (+49 6172) 16-0
(33 1) 69 82 60 60
Great Britain
Hewlett-Packard Ltd.
Eskdale Road, Winnersh Triangle
Wokingham, Berkshire RG11 5DZ
1-30
Installing
Hewlett-Packard Sales and Service Oces (continued)
INTERCON FIELD OPERATIONS
Headquarters Australia Canada
Hewlett-Packard Company Hewlett-Packard Australia Ltd. Hewlett-Packard Ltd.
3495 Deer Creek Rd. 31-41 Joseph Street 17500 South Service Road
Palo Alto, California 94304-1316 Blackburn, Victoria 3130 Trans-Canada Highway
(415) 857-5027 (61 3) 895-2895 Kirkland, Quebec H9J 2X8
Canada
(514) 697-4232
China Japan Singapore
China Hewlett-Packard Company Yokogawa-Hewlett-Packard Ltd. Hewlett-Packard Singapore Ltd.
38 Bei San Huan X1 Road 1-27-15 Yabe, Sagamihara Pte. Ltd.
Shuang Yu Shu Kanagawa 229, Japan Alexandra P.O. Box 87
Hai Dian District (81 427) 59-1311 singapore 9115
Beijing, China (65) 271-9444
(86 1) 256-6888
Taiwan
Hewlett-Packard Taiwan
8th Floor, H-P Building
337 Fu Hsing North Road
Taipei, Taiwan
(886 2) 712-0404
1-31
Installing
2
Performing Guided Setups
and Calibrations
Performing Guided Setups and Calibra-
tions
This chapter shows you how to perform a guided setups, a guided
calibrations, and manual calibrations. Calibrating the precision re ectometer
consists of balancing the receiver and then calibrating the magnitude. These
two procedures ensure maximum accuracy for your measurements. They
remove DC osets and polarization sensitivity. They also set a calibrated
reference level.
Guided setups not only calibrate the instrument, but they also select the
source and display instructions for both pigtailed and non-pigtailed devices.
Manually calibrating the instrument is generally faster that using the guided
calibration.
When the instrument is calibrated, the status indicator C
appears on the display's left-hand side.
2-2
Performing Guided Setups and Calibrations
Contents Running Guided Setups and Calibrations : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-6
To perform a guided setup (devices with pigtail) : : : : : : : : : : : : : : : : : : : : : 2-7
To perform a guided setup (devices without pigtail) : : : : : : : : : : : : : : : : : 2-13
To perform a guided calibration : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-18
Performing Manual Calibrations : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-20
To balance the receiver : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-23
To calibrate the magnitude : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-25
To calibrate for an external source : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-26
To turn o calibration data : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-28
To enter the standard's re ection percentage : : : : : : : : : : : : : : : : : : : : : : : 2-28
To turn chromatic dispersion correction on and o : : : : : : : : : : : : : : : : : : 2-28
To use the Option 001 cable tray : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : : 2-29
NOTE
In order to ensure a successful calibration, clean all ber-optic connectors prior to the calibration. Refer
to \Cleaning Connections for Accurate Measurements" in Chapter 1 in this chapter.
Some hardware is You'll need the following hardware, supplied with HP 8504B, to calibrate the
required instrument:
A set of matched-length cables.
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 During calibrations and subsequent measurements, two cables must be
ensure response is connected to the precision re ectometer. One cable connects the device
visible being measured to the front-panel TEST PORT. The other cable connects the
front-panel REFERENCE EXTENSION A and B connectors. The REFERENCE
EXTENSION cable must be equal in length (or slightly shorter) than the TEST
PORT cable.
The relative lengths of these two cables determine the position of the Fresnel
re ection (from the end of the TEST PORT cable) on the screen. If the
REFERENCE EXTENSION cable is too long or too short, the measured response
may not be visible on the screen. This is shown in the following gure.
Cable lengths determine response position.
2-4
Performing Guided Setups and Calibrations
Changing the span does Any calibration performed in less than full span is still valid after the start or
not aect calibrations 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 REFERENCE EXTENSION A and
B on the front during or after a calibration. Moving this cable changes the polarization and voids
the calibration. If you have an Option 001 accessory kit, use the kit's cable tray to help keep the
reference extension cable stationary.
Unlike the reference-extension cable, the test-port cable is unaected by changes in polarization due to
cable bending. Therefore, this cable may be moved without degrading the calibration.
Keep the balance knobs stationary
Do not move either of the front panel reference-polarization balance knobs after calibration. Moving
the knobs compromises the calibration.
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
4PRESET5 or 4SYSTEM5 keys. Using the 4PRESET5 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
the polarization balance using the front-panel knobs, the precision
re ectometer mathematically compensates for any polarization imbalance
between the TEST PORT cable and the REFERENCE EXTENSION paths. To
complete the calibration, a standard cable of known re ectance is used to
calibrate the magnitude. The displayed response is scaled to match the value
speci ed for the standard in percentage of re ectance.
2-6
Performing Guided Setups and Calibrations
Running Guided Setups and Calibrations
To perform a guided setup
(devices with pigtail)
1. Press 4PRESET5 and then GUIDED SETUP . NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
2. Press a softkey to select the wavelength.
3. Press CLASSIFY DEVICE and then PIGTAIL .
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN NNNNNNNNNNNNNNNNNNNNNNN
Select cables 4. Press CONNECT CABLES .
NNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNNN
5. Measure the length of the device's pigtail. Include the length of any
additional cable used to connect the device to the front-panel TEST PORT
connector.
6. Based on the length measured in the preceding step, use the following
chart to assemble a ber-optic cable for the reference path.