They have a simple structure, low noise, and a high overload point (typically -3dBm, up to 0dBm). PIN diodes do not amplify signals, so they rely on the TIA to convert weak photocurrents into usable voltage signals. 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). They mainly consist of optoelectronic components (such as optical transmitters and receivers), functional circuits, and optical interfaces, aiming to achieve the functionalities of optical-to-electrical and electrical-to-optical signal conversion in optical fiber communication. Below is a detailed breakdown of its internal structure: 1. Optical Transmission Section Laser (Light Source): Generally, a laser diode (LD) or light-emitting diode (LED) is used as the light source.