1. Incoming material inspection, patch inspection2

ETU-LINK will conduct incoming material inspection and patch inspection before assembling optical modules. Among them, incoming material inspection refers to the manufacturer's inspection of incoming components before assembling optical modules, such as testing whether the optical transmitting assembly (TOSA), optical receiving assembly (ROSA) and optical transmitting and receiving assembly (BOSA) are qualified, so as to ensure that the optical Module quality, reducing rework rate and defect rate, while avoiding damage to expensive optical components. The patch inspection is mainly to check whether the PCB board patch is correct and whether there is pollution, so as to ensure the performance of the optical module.

2. Optical power detection

The average output optical power is an important parameter of the optical module, which directly affects the communication quality.

3. Extinction ratio and optical modulation amplitude (OMA) test

The extinction ratio is one of the parameters used to measure the quality of the optical module. The extinction ratio refers to the ratio of the optical power of the high level (that is, all "1" codes) and low level (that is, all "0" codes) output by the laser. Through The test detects whether the laser is operating within the optimum bias point and optimum modulation efficiency. In addition, optical modulation amplitude (OMA) is also a measure of the power difference when the laser is turned on and off. Both are detected with mainstream optical oscilloscopes. At the same time, in the extinction ratio detection, you can see the relative amplitude of the "1" level and "0" level of the optical signal. The sensitivity will be higher. At the same time, the extinction ratio is inversely proportional to the optical power. During the test, it can be found that the larger the extinction ratio, the smaller the emitted optical power.

4. Bit error rate and receiving sensitivity test

The bit error rate is one of the parameters to measure the ability of the optical module to transmit symbols correctly. The bit error rate refers to the ratio of the number of errored code elements received after the photoelectric conversion at the receiving end to the number of code elements given by the output end of the bit error meter within a specified time. The bit error rate test needs to receive the optical signal with pseudo-random signal output by the optical module under test through the standard receiving tube test unit, and use the standard receiving tube test unit to demodulate and compare to complete the bit error rate test.

5. Eye diagram test

Eye diagram testing and adjustment is an important stage to ensure that the optical module gets the best signal. The so-called eye diagram is formed by superimposing and accumulating all the captured waveforms according to every three bits through the afterglow function of the oscilloscope. The digital signal quality of the optical module can be seen from the eye diagram test results. By carefully observing the eye height of the eye diagram, The performance of the optical module is judged by eye width, jitter, duty cycle, etc. The larger the eye, the smaller the intersymbol interference and the better the performance of the optical module.