OMM Series
User Manual
Document No.: UM-OPM-2 Rev. A
File Name:OPM-2 Optical Power Meter User Guide Draft
Confidential
6
2.3
Performing a Fiber Loss Test
An important part of certifying a newly constructed fiber network is performing a Fiber Loss Test. This
test confirms the loss in the segment of fiber being tested is within acceptable limits. The test is
performed by connecting a Laser Source at one of the fiber to be tested inserting a signal at a known
level. A power meter is connected at the other end of the fiber and the Power is measured. The measured
loss through the fiber must fall within the loss budget specified in the network design. A Fiber Loss Test
may also be performed when a new reel of fiber optic cable is received to ensure it was not damaged in
shipment and meets minimum performance standards. To perform a Fiber Loss Test with an OMM Series
meter do the following steps:
1.
Set the Reference level on the OMM if it is used as the Power Meter
a.
Connect the OMM power meter input and the optical laser source (OLS) with a short
jumper.
b.
Configure the output of the optical laser source to the desired wavelength and power
output.
c.
On the OMM, press and hold the Reference Key. Two beeps will sound and the display
will indicate 0.00dB. This provides a “Reference” level that will allow the power meter
to measure signal level differences when measuring fiber loss.
2.
Repeat these steps for all wavelengths to be tested while ensuring the laser source and OMM are
always on the same wavelength. This is where the TWIN functionality can ensure this is done
correctly.
3.
Connect the Optical Laser Source to one end of the fiber to be tested
4.
Connect the OMM power meter input connector to the other end of the fiber to be tested.
5.
The measurement displayed (in dB) will be the loss through the fiber under test.
6.
If the test result is to be saved/documented, press and hold the Load key on the OMM for > 2
seconds. The file name/number will be displayed briefly at the bottom of the display.
7.
If additional wavelengths are to be tested, repeat process starting with Step 1 to reset the
reference level with new wavelength. For tests done when the ends of the fiber are at different
locations, set and store a reference level for each wavelength first. The meter will automatically
store the correct reference level for each wavelength and recall it whenever the wavelength is
selected.
Note: The OMM can also be used as the Optical Laser Source. In this scenario, a separate power meter
will be required to run the loss tests. If testing is being done on a fiber spool and separate locations are
not required, the OMM can be used as both the OLS and OPM, thus eliminating the need for two separate
devices.
