OPTOKON OFT-920 User manual

is registered trademark of OPTOKON, a.s. Other names and trademarks mentioned herein may be the
trademarks of their respective owners.
OPTOKON, a.s. Cerveny Kriz 250, 586 01 Jihlava, Czech Republic
tel. [phone], fax [phone], WWW.OPTOKON.COM, [email protected]Z
s/w: 3.2
09/12/2016
OFT-920
Ruggedized Optical Loss Test
Set
USER MANUAL
Revision 3.2

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is the registered trademark of OPTOKON, a.s. Other names and trademarks mentioned
herein may be the trademarks of their respective owners
All rights reserved. No parts of this work may be reproduced in any form or by any means - graphic, electronic,
or mechanical, including photocopying, recording, taping or information storage and retrieval systems - without
the written permission of the publisher.
Products that are referred to in this document may be either trademarks and/or registered trademarks of the
respective owners. The publisher and the author make no claim to these trademarks.
While every precaution has been taken in the preparation of this document, the publisher and the author
assume no responsibility for errors or omissions, or for damages resulting from the use of information
contained in this document or from the use of programs and source code that may accompany it. In no event
shall the publisher and the author be liable for any loss of profit or any other commercial damage caused or
alleged to have been caused directly or indirectly by this document.
OPTOKON, a.s.
Cerveny Kriz 250
586 01 Jihlava
Czech Republic
tel. [phone]
fax [phone]
WWW.OPTOKON.COM
[e-mail]

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Content
1Introduction.................................................................................................. 4
2Features........................................................................................................6
3Application ....................................................................................................6
4Accessories ...................................................................................................6
4.1 Standard........................................................................................................................6
4.2 Options:........................................................................................................................6
5Specifications ................................................................................................7
5.1 Light Source.................................................................................................................7
5.2 Power Meter.................................................................................................................7
5.3 Loss Test Set ................................................................................................................7
6Safety information......................................................................................... 8
7Maintenance.................................................................................................. 9
7.1 Battery care and replacement.......................................................................................9
7.2 Instrument care...........................................................................................................11
7.3 Optical connector care................................................................................................11
8Button function description........................................................................... 12
8.1 Menu #1 .....................................................................................................................13
8.2 Menu #2 .....................................................................................................................14
8.3 Menu #3 .....................................................................................................................15
8.4 Menu #4 .....................................................................................................................16
8.5 Menu #5 .....................................................................................................................17
SAVE RESULT ...................................................................................................................17
LOAD RESULT...................................................................................................................17
UPLOAD MEMORY...........................................................................................................18
9Measuring loss............................................................................................. 19
9.1 Basic theory................................................................................................................19
9.2 Method 6 - two instruments .......................................................................................20
9.2.1 Setting the reference .........................................................................................20
9.2.2 Measuring Loss.................................................................................................21
9.3 Method 6 - one instrument.........................................................................................22
9.3.1 Setting the reference .........................................................................................22
9.3.2 Measuring Loss.................................................................................................23
9.4 Method 7 - two instruments .......................................................................................24
9.4.1 Setting the reference .........................................................................................24
9.4.2 Measuring Loss.................................................................................................25
9.5 Method 7 - one instrument.........................................................................................26
9.5.1 Setting the reference .........................................................................................26
9.5.2 Measuring Loss.................................................................................................27
10 Ordering information .............................................................................. 28
10. Setting up data transfer.......................................................................... 29
11. Power loss and decibels.......................................................................... 32
12. Notes..................................................................................................... 33
13. Calibration, service center....................................................................... 36

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1Introduction
The OFT-920 optical test set is designed for testing optical networks terminated with
connectors operating in harsh environments. It combines both a light source and
optical power meter in one common box. The OFT-920 test set is designed to meet
the tactical military and broadcast industry demand. The ruggedized aluminum case
makes the unit ideal for field operation.
General description:
-front view

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-top view:
-rear view:

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2Features
Expanded Beam and ferrule harsh environmental connectors
Ruggedized aluminum case
Multimode (MM) or single mode (SM) applications
Simultaneous testing of all 2/4 fibers
Internal memory: up to 2000 measurements
Displayed units: dBm, dB
High dynamic range
Up to 4 light source combinations
Built-in charger, battery status indicator
Easy to use with menu navigation
3Application
Optical network measurements
Fiber continuity testing
4Accessories
4.1 Standard
Power charging adaptor
Soft carrying case
USB Cable
Cleaning swabs
4.2 Options:
Reference patchcord

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5Specifications
5.1 Light Source
Light Source:
Output power
Note:
LD 850 nm, LED 850, 1300 nm
-26 dBm (62.5/125 µm fiber)
LD 1310, 1490, 1550, 1625 nm
-16 dBm
typ. value
Stability (1 hour, delta/2):
tested after 20 min warm up
temperature 23 ± 1°C
LD 850 nm, LED 850, 1300 nm
± 0.03 dB
LD 1310, 1490, 1550, 1625 nm
± 0.05 dB
5.2 Power Meter
Power Meter:
Photo detector
InGaAs
Working
wavelengths
Multimode: 850, 1300 nm
Singlemode: 1310, 1490, 1550, 1625 nm
can be customized
Uncertainty
± 12%
1310, 1550 nm @ -20 dBm
Resolution
0.1
Dynamic range -55 dBm to +10 dBm
-53 dBm to +17 dBm
1300, 1310, 1490, 1550, 1625
nm
850 nm
5.3 Loss Test Set
Optical Test Set
Dimensions
145 x 145 x 56 mm
without connectors
Weight
400 g
with battery
Temperature operating
storage
Humidity (non condensing)
-10 to +50 °C
-40 to +70 °C
0 to 95%
Operating temperature
-10 to +50 °C
Battery working time
> 20 hrs
One source operation
Battery life time
> 2 years (1000 cycles)

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6Safety information
This equipment complies with the following safety classifications:
IEC825-1 and 21CFR1040: Class1
This applies to laser and LED options up to 1 mW, above 700 nm. Devices in this
category are classified as safe for use by technicians under normal viewing, as long
as magnifying devices are not used.
It is the responsibility of the user to gain adequate training and familiarity
with the relevant safety issues and work practices before using this
equipment.
WARNING!
•Never use magnifying devices to inspect optical fiber ends unless you are sure
that no optical power is being emitted.
•Use only magnifying devices with a built-in infra-red filter to ensure safety.
•During operation, testing or maintenance of a fiber optic system, never look
into an active fiber optic cable. Infrared radiation may be present and
permanent eye damage can result.
•Avoid direct exposure to the beam.
•Do not activate the laser when there is no fiber attached to the optical output
connector
Under no circumstances should you look into the end of an optical cable attached to
the optical output when the device is operational. The laser radiation can seriously
damage your eyesight.

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7Maintenance
7.1 Battery care and replacement
OFT-920 is equipped with a charger and powered by built-in, three-cell, NiMH battery
pack. Rated voltage is 3.6 V, recommended capacity is 800 [mAh] (for 20 hrs
operation). Use only the charger supplied by OPTOKON (DC 5 V, USB connector).
Recommended charge time is 12 to 14 hours. For replacement of the battery must
be removed bottom cover (by losing 4 screws under rubber covers):

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After opening disconnect battery connector and remove battery pack:
Insert new battery and connect the battery connector (be careful for polarity). Take
back the bottom panel, tighten all screws and insert back the rubber covers.

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7.2 Instrument care
•During storage and transport keep the instrument in its carrying case to
protect against crushing, vibration, dust and moisture.
•Where possible, keep the instrument away from strong sunlight.
•Clean the instrument housing using alcohol or other cleaning agents. Acetone
or other active solvents may damage the case.
•The instrument is resistant to normal dust and moisture, however it is not
waterproof. If moisture gets into instrument, dry it out carefully before using it
again.
7.3 Optical connector care
•Cleanliness will affect the performance of an optical fiber system.
•All connectors and fiber end faces need to be clean prior to testing.
•Clean all connectors, adapters, and attenuators before making any
connections.
•Use appropriate optical cleaning supplies to keep connectors and adaptors free
from contamination.
•The following cleaning materials are recommended and should form part of
your cleaning kit:
•Lint-free laboratory wipes.
•Isopropyl alcohol in pressurized dispenser
•Lint free pipe cleaners
•Clean, dry, oil-free compressed air

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8Button function description
[ON/OFF]
Press to turn the unit on.
Press to turn the unit off.
After switching on, the type of device, serial number and firmware version will be
displayed.

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8.1 Menu #1
[MENU]
-starts menu
-goes to menu #3
[LOSS]
-activates the relative power measurement mode (dB)
-recalls the last set reference for selected wavelength
-goes to menu #2
[
λ
]
-selects the wavelength (multimode - 850, 1300 nm, single mode -1310, 1490, 1550
or 1625 nm)

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8.2 Menu #2
[HOME]
-return unit into absolute power measurement mode (dBm)
-goes to menu #1
[REFF]
-sets and stores the new reference for the selected wavelength
-requires confirmation [OK]
[MENU]
-starts menu
-goes to menu #3

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8.3 Menu #3
[SETUP]
-goes to menu #4
-allows to activate / deactivate Auto Off and Backlight
[LS]
-goes to Light Source screen
−press λ to select the wavelength
−press OK to return to Power Meter screen
[MEMORY]
-start work with the internal memory
-goes to menu #5

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8.4 Menu #4
[AOFF]
-activates or deactivates Auto Off feature.
If activated, the unit will turn off after approximately 10 minutes of no activity.
[B/L]
-turns the Display Backlight On and Off
[LIMIT]
-sets limit (dB) for measured fibers - A1, A2, B1, B2
-by using +and –keys set limit, and confirm “OK”
minimum value is 0.5 dB, maximum 25 dB, step 0.5 dB.
-for measuring without limit set “OFF”
-when the limit is set, and unit is in relative power measurement mode, the screen
shows:
pass – the loss is lower than the limit
fail – the loss is higher than the limit
overpower – indicates gain, clean the connectors and make a reference again

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8.5 Menu #5
[UP], [DOWN], [OK]
Use these buttons to select an appropriate submenu.
SAVE RESULT
[+ MEM -]
-selects the memory cell
[SAVE]
-saves the result into the selected memory cell and exits the menu
NOTE: Memory cell number is automatically INCREMENTED BY 1 after [save]
command.
LOAD RESULT
[+ MEM -]
-browses through memory cells
[HOME]
-exit menu, return to Power Meter screen

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UPLOAD MEMORY
-sends the whole content of the internal memory to a PC via USB
ERASE MEMORY
-erases the whole internal memory
HOME
-exit menu, return to Power Meter screen

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9Measuring loss
9.1 Basic theory
Loss measures the signal degradation in a fiber optic cable. The light source injects
an optical signal of the appropriate wavelength into the fiber and the power meter
measures the received signal at the same wavelength.
There are two different measuring methods:
•Method 6
•Method 7
according to IEC 874-1 4.4.7.4.
Power measurement is the basis of optical testing and determines the power budget
of the fiber optic link by comparing the power of the transmitter and the sensitivity of
the receiver. This difference is the maximum acceptable loss. The power loss is
caused by different phenomena such as attenuation of the fiber, dirty connector
mating faces, connector misalignment, loss of splices and other events as sharp
bends of fiber…
The "end to end" loss test is the most often used acceptance test of power loss in
fiber optic links. The test is based on measuring the power difference at the input
and output of the link.
One or two OFT-920 instruments are used for this test, where the light source port
acts as a transmitter and the optical power meter port as a receiver.
The "end to end" test has two steps:
1. Setting the reference
2. Measuring the loss

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9.2 Method 6 - two instruments
For method 6, two master cords are used to set the reference. Method 6 cancels the
effects of the master cords for all subsequent measurements.
9.2.1 Setting the reference
1. Connect the first master cord to the light source port of first OFT-920
instrument.
2. Connect the second master cord to the power meter port of a second OFT-920
instrument.
3. Connect two cable ends.
4. Power on the first OFT-920 instrument (light source).
5. Push [MENU], [LS].
6. By pushing [
λ
] select the appropriate wavelength.
7. Power on the second OFT-920 instrument (power meter).
8. By pushing [
λ
] select the appropriate wavelength range.
9. Activate relative power measurement mode - by pushing [LOSS].
10. Set LIMIT if necessary – push [MENU], [SETUP], [LIMIT] and after setting the
appropriate value (by + and – keys) confirm by [OK].
11. Set and store the new reference for the selected wavelength - by pushing
[REF], confirm by [OK].
(pic.1)