After the finished optical module is produced, a complete test process must be carried out, and the test method is a very professional issue. All steps must be carried out and all parameters must meet the requirements to ensure that the optical modules are sold without any quality problems. The following is the complete process of post-production testing of optical modules.

　　①Light-emitting and receiving test.

　　The output optical power is an important parameter that determines the transmission distance and quality of the optical module. Too high or too low is not good; the receiving sensitivity can determine the sensitivity of the optical module. Generally, the higher the optical module rate, the worse the receiving sensitivity;

　　② Eye diagram, extinction ratio test.

　　The shape of the eye diagram is similar to that of the eye. It is the result of multiple acquisitions and superposition of digital signals by the oscilloscope. It can intuitively reflect whether the measured signal is lost and whether the signal transmission is good. The extinction ratio is one of the parameters to measure the quality of the optical module. The larger the extinction ratio, the stronger the ability to receive and identify the optical signal, and the higher the receiving sensitivity. The extinction ratio is inversely proportional to the optical power. During the test, it was found that the larger the extinction ratio, the smaller the luminous power;

　　③High and low temperature aging test.

　　The application environment of the optical module is different, and the working temperature is also different. Before the optical module leaves the factory, a high and low temperature aging test must be carried out in the aging box to verify whether the performance index of the optical module in the extreme environment can still reach the standard;

　　④ Compatibility connection test.

　　Insert the optical module into the switch of the corresponding brand for detection and connection test. If it can be connected, it means that the optical modules are compatible and the optical modules can communicate. If it cannot be connected, further testing is required;

　　⑤ End face cleaning

　　In the various testing links of the optical module, some dirt and scratches will inevitably appear, which need to be observed through a microscope. If there is no problem, it can be packed and shipped. If there is a problem, it needs to be dealt with.