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Setting Up Optical Paths
Station A
West
Fiber jumper
Optical power meter
a
Measure the optical power at the OUT port on the FIU board at the transmit end and record
a.
the reading as
b
Measure the output optical power of the ODF at the transmit end and record the reading as
c
Measure the input optical power of the ODF at the receive end and record the reading as
d
Measure the input optical power at the IN port on the FIU board at the receive end and record the
d.
reading as
Subtract reading b from reading a to determine the fiber insertion loss on the line side of the upstream station. This
insertion loss must be lower than 1 dB. The fiber connectors on span 1 require cleaning if the insertion loss is
greater than 1 dB. The fibers on span 1 need to be replaced if the insertion loss remains greater than 1 dB after the
fiber connectors are cleaned.
Subtract reading d from reading c to determine the fiber insertion loss on the line side of the downstream station. This
insertion loss must be lower than 1 dB. The fiber connectors on span 2 require cleaning if the insertion loss is greater
than 1 dB. The fibers on span 2 need to be replaced if the insertion loss remains greater than 1 dB after the fiber
connectors are cleaned.
After ensuring that the optical paths on spans 1 and 2 are functioning properly, calculate the actual line attenuation
between the two stations according to the Line attenuation = a - d + 2 formula. (In the formula, 2 indicates 2 dB, the
insertion loss of each FIU board.) The line attenuation must be equal to or lower than the line attenuation specified in
the design documents. In the event that the line attenuation does not fall within the specified range, inform the
customer to rectify or replace the fibers on span 3.
After all issues are resolved, restore all fibers and cable connections, and set up all optical paths from west to east.
Repeat the preceding operations to set up all the optical paths from east to west and ensure that the optical paths
between the existing stations are functioning properly.
a
b
c
45
Station B
d
b.
c.
East
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