Network topology: Originally, the system uses one-level optical split and the split ratio is 1:8. Later, the customer connects a 1:16 optical splitter to the 1:8 optical splitter. The three ONUs are connected to the 1:16 optical splitter.
During deployment in an office, three ONUs frequently go online and offline.
l The ONU receive optical power is larger than the overload optical power.
l The ONU receive optical power is smaller than the sensitivity.
l There is abnormal attenuation on ODN lines.
Step 1 Test the ONU receive optical power. It is found that the receive optical power of the three ONUs is approaching the sensitivity.
Step 2 Analyze the total split ratio of the three ONUs. It is found that the total split ratio is 1: (16 x 8) = 1:128, which is too large and therefore causing too large attenuation
Step 3 Change the 1:16 optical splitter to a 1:4 one. Then, the fault is rectified.
Step 4 Such a fault does not recur in the next week.
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