Customer Return Analysis Report of 10G BIDI 1490/1550nm 80km

Our company conducts normal temperature testing on the modules returned by customers to confirm:

1. Among the three modules of SFP-10G-BXU80, the module with serial number SN:HL23H0904011 has low transmit optical power and abnormal eye diagram; the module with serial number SN:HL23H0904017 cannot receive and connect; the module with serial number SN:HL23H0904012 has normal performance indicators.
2. Among the four modules of SFP-10G-BXD80, the module with serial number SN:HL23H0904026 has low current and does not work; the modules with serial numbers SN:HL23H0904021, SN:HL23H0904033, and SN:HL23H0904036 have normal performance indicators.

Micro-debugging of the upper-level software cannot improve the luminous power and eye diagram quality. It can be judged that the transmitting device has moved, and the only option is to replace the device. The luminous power and eye diagram after replacement are:

When testing the module's reception with a standard module, the BERT displays out-of-step:

When receiving a signal without optical power, the DDM information is displayed abnormally, with an actual display of 2.66dBm. When receiving a signal without optical power, the DDM information is displayed as -40dBm:

After opening the module shell, use the multimeter voltage range to measure the power supply voltage (3.3V) and reverse high voltage (about 30V) received by the APD. The measurement result shows that the reverse high voltage output is low, only 6.4V:

The power supply voltage is normal 3.24V:

Reverse high voltage abnormality 6.4V:

After removing the APD receiving flexible board, the reverse high voltage output of the main board was measured. The result was 32.5V, which is within the normal range:

It can be judged that the APD receiver has been burned out and the reverse high voltage has been pulled down. After replacing the new BOSA device, the receiving end voltage is measured again after micro-adjusting to the optimal sensitivity point. The measured voltage value is normal and can be connected:

After opening the cover, it was detected that the output voltage of the motherboard MOS tube was low, only 1.6V, and the normal voltage value is 3.3V:

The initial judgment is that the MOS tube is broken. After replacing the new MOS tube, its voltage output is measured again, and the normal value is 3.3V:

After reassembly, the current and various performance indicators were tested, and the test results were normal.

• When received the product, there was no dust plug on SFP, and tiny particles entered the module, making it very dirty inside and the device displacement ;
• There are two main possibilities for APD burnout: one is electrostatic breakdown; the other is that an optical signal with excessive optical power is input during use or detection, causing the avalanche diode in the APD to exceed the limit value and be damaged.

A few suggestions during use:

• Pay attention to anti-static protection;
• Keep the fiber optic jumper head clean during use.

Please use dust plugs to protect the module when unplugging it after use.