As illustrated in typical SFP internal structure diagrams, the module's core components include an optical transmitter assembly (TOSA), laser driver, optical receiver assembly (ROSA)—some high-sensitivity modules (like L16. The working. 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. The optical module is usually composed of Transmitter Optical Subassembly (TOSA. This comprehensive guide breaks down the internal structure, core components (TOSA, ROSA, lasers), and operational mechanisms of SFP optical modules, enriched with technical insights and real-world applications.