In a WDM network expansion project, the DCP board is used for 1+1 protection at the WDM side and the OTU is the LSX. After the optical fiber is connected according to the signal flow, the MCA board is used to perform wavelength channel analysis. It is found that one wavelength cannot be detected.
Check the fiber jumper. Test the Rx optical power at TI1 on the DCP board. The value is -1.58 dB, which is normal. Then, test the Tx optical power at the TO11 and TO12 optical interfaces. The values are -11.23 db and -11.58 dB respectively. Query the insertion loss on the DCP. The result is that TI1-TO11 ( TI1-TO1B2) ≤ 4. Therefore, the problem is caused by the board. Then, check the Tx optical power at other optical interfaces. The insertion loss at each optical interface is about 3 dB, which is normal.
Possible causes are as follows:
1. The fiber jumper is faulty.
2. The DCP board is faulty.
During troubleshooting of a WDM problem, perform check segment by segment according to the signal flow.