1. The choice of optical splitter is determined by the link design of the PON system. Putting aside the dispute between EPON and GPON, the current technology in the PON network can already achieve an optical splitting ratio of 1×128, which brings great benefits to the ODN design of PON. Great flexibility. Therefore, when designing optical links, it is important to plan the link based on the transmit and receive optical power budget of the OLT PON. Generally, the ONUs that need to be deployed in the entire system are divided into regions to determine the coverage of the PON.