As one of the cores of medium and long haul optical communication, optical transceiver modules play the optical-electric/electric-optical conversion function of optical signals. The interior of transceiver modules is composed of optical devices, functional circuits and optical interfaces, etc. Among the optical components inside the optical module, the major components are the transmitter optical sub-assembly (TOSA) and the receiver optical sub-assembly (ROSA) https://www.glsunmall.com/fiber-optic-articles/what-is-tosa-rosa-and-bosa-in-optical-transceivers.html