Single fiber modules (BiDi) use one fiber for both transmitting and receiving data. They use a thin fiber. 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. Optical modules typically have an electrical interface on the side that connects to the inside of the system and an optical interface on the side that connects to the outside. There are different types of fiber optic cables because each type is optimized for specific applications that have unique requirements for bandwidth, transmission distance, and environmental factors.
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