After the input electrical signal is processed by the internal driver chip, it drives the laser diodes (LD) or light-emitting diodes (LED) to emit a modulated optical signal at a corresponding rate. An optical module usually consists of an optical transmitting device (TOSA, including a laser), an optical receiving device (ROSA, including a photodetector), functional circuits,main control circuit board (PCBA), housing and optical (electrical) interface and other components. How do optical. That is, metal medium communication represented by coaxial cables and network cables is gradually being replaced by optical fiber media. ” It's one of the most common ways. Optical modules are devices used to connect network devices, transmit and receive data between network devices, and can be used to convert optical and electrical signals.