Problem Description

Sites A-B are 125 kilometers apart, using SSN3SL16 single boards and transmitting through BA optical amplification, and when checking the performance, it is found that there are a few regeneration and multiplexing segment errors in the N3SL16 single boards docked at sites A and B .

Alarm message

Regeneration segment error code, multiplexing segment error code.

Processing

1. Measure the optical power on site and find that the optical power is -18dBm, which meets the requirement and excludes that the optical power is too low and leads to BER.

2, query information, SSN3SL16 V-16.2Je optical module support transmission 140 kilometers, while the scene 125 kilometers, the distance meets the requirements.

3, the scene will be SSN3SL16 plus optical attenuation after the use of pigtail self-loop, found that the BER disappeared, put through the BER appeared again.

4, replace the BA optical amplifier single board, the problem can not be solved, to rule out the optical amplifier single board problem.

5, re-replace a SSN3SL16 single board, found that the error code disappears, compared before and after the two SSN3SL16 single board, found that: the single board FPGA version of the error code is 130, and no error code single board FPGA version of 200.

6, after R & D to confirm: the problem is due to the SSN3SL16 single-board optical module scrambling signal design reasons lead to long-distance transmission may produce a small amount of error code, affecting the transmission performance.

7, SSN3SL16A 200 version of the FPGA has solved this problem, the scene will SSN3SL16 V-16.2JeFPGA upgrade to 200 version, while the single board software upgrade supporting the disappearance of the error code.

Root Cause

1、The line attenuation is too large, and the optical power is too low leading to BER.

2、Transmission distance is too large, beyond the transmission distance of the single board, performance degradation leads to BER.

3、BA optical amplifier failure leads to BER.

4、SSN3SL16 single board failure leads to BER.

Recommendations and Summary

None.