Huawei OptiX PTN Series Quick Installation Manual page 40

For 50 Gbps series optical modules, pay attention to the following points:
Optical Maximum
Module Average
Type Transmit Optical
Power
50GBASE-
4.2
LR (10km)
50GBASE-
6.6
ER (40km)
4 Checking Optical Link
Since the 50G/200G optical module link uses the PAM4 encoding technology, the link is more sensitive to multipath
reflection interference of signals. If the fiber link connector, fiber section, or fiber splicing surface is dirty, optical signals are
reflected back and forth on the fiber link, causing interference due to co-channel noise on the receive side. As a result, the
optical link is unstable or intermittently disconnected.
Before installing the 50G/200G optical module, you are advised to use an OTDR meter to check the optical link. The check
method is as follows:
Remove optical
modules from
both sides and
remove optical
fibers.
Because the transmit optical power of the OTDR meter is much higher than the damaged optical power threshold at the
receive end, the optical fiber must be removed from the optical module when the OTDR meter is used to test the optical
path quality.
Minimum
Average
Transmit Optical
Power
-4.5
0.4
Check the receive and
transmit end faces of
the optical module
using the fiberscope.
If dirty substances
exist, use the
cleaning tool.
37
Damaged Optical
Power Threshold
at the Receive
End
The damaged optical power
threshold is greater than the
maximum average transmit
5.2
optical power, posting low self-
loop risks.
The damaged optical power
threshold is 9dBm lower than
the maximum average transmit
optical power and 2.8dBm
lower than the minimum
-2.4
average transmit optical power,
posing high self-loop risks. In
this case, an optical attenuator
must be configured for self-loop.
Check the pugtail
end face using the
fiberscope.
If dirty substances
exist, use the
cleaning tool.
Description
Check the optical path
insertion loss and
reflection using the OTDR
tester.
Process the segment
based on the check
result.