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. The Ultimate Guide to Principles, Types, and Troubleshooting Optical Modules (also known as Optical Transceivers) are critical components in fiber optic communication systems. As the core optoelectronic devices operating at the Physical Layer of the OSI model, their primary function is to perform. Average optical power refers to the optical power outputted by the optical module's transmitter under normal working conditions, which can be understood as the intensity of light. The transmitted optical power is related to the proportion of "1"s in the transmitted data signal; the more "1"s, the. The invention discloses an optical module debugging system, which comprises a debugging board, a debugging communication mainboard and a debugging host machine, wherein the debugging board comprises a differential crystal oscillator which is used for providing data electric signals for a debugged. In the era of 5G, AI, and high-speed data centers, optical modules serve as the core bridge for converting electrical signals to optical signals (and vice versa), enabling fast, reliable data transmission across networks. Among various optical module form factors, SFP (Small Form-Factor Pluggable). The Transmitter Optical Sub Assembly (TOSA) is responsible for the emission of light. Its primary function entails converting electrical signals into optical signals. These modules leverage advanced signal processing, modulation, and high-speed interfaces to provide high bandwidth, low latency, and reliable performance.