The input optical power of the OTU board is abnormal due to a fault of the OPU board.
Symptom
In a single-channel ring network, the input optical power of an OTU board drops from 0 dBm to -7 dBm, -15 dBm, or -62 dBm.
This ring network bears the SDH service and is configured with the multiplex section protection (MSP).
Cause Analysis
The launched optical power of the opposite OTU is abnormal, or the line amplifier unit is faulty.
Procedure
- By checking whether there are abnormal alarms against the input optical power of the opposite OTU board, you can find that the parameters of the opposite OTU board are proved normal. This indicates that the launched optical power of the opposite OTU is normal.
- The input and output optical power of the opposite amplifier board are also checked normal.
- The input and output optical power of the local amplifier board, however, are checked abnormal. The input optical power of the local amplifier board is constant, whereas the output optical power of the local amplifier board is abnormal. This indicates that the local amplifier board is faulty.
- After you replace the local amplifier board, the system is restored.
Reference Information
- When you find that the output optical power of the local OTU is abnormal, check the following items:
- Input and output optical power of the opposite OTU board
- Input and output optical power of the opposite amplifier board
- Input and output optical power of the local amplifier board
- If the anomaly of optical power occurs at random, perform the following steps:
- Check whether any fiber jumper is loose or bent.
- Clean the fibers and connectors.
- Perform an optical time domain reflectometer (OTDR) test under the customer's consent.
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