Optical module PCB composition: mainly includes four key parts: PCBA (Printed Circuit Board Assembly), TOSA (Optical Transmitter Submodule), ROSA (Optical Receiver Submodule), and the housing. Designing and producing these complex PCBs presents formidable challenges, requiring a convergence of disciplines—from high-frequency signal integrity and advanced thermal. Integrated circuits and reference designs help you create a smaller and faster optical module design used in high-bandwidth data communication applications. Whether you are creating a 100-Gbps or 400-Gbps, small form-factor pluggable (SFP) module, SFP+ transceiver, XFP module, CFP, X2/XENPAK module. Optical PCBs [^1] integrate light-based data transmission with electrical circuits using polymer waveguides and photonic chips, enabling 400Gbps+ speeds for 5G networks and AI servers while reducing power consumption by 40% compared to conventional boards. This article takes you through this PCB's ins and outs, exploring how it works, its advantages over other circuit boards. Definition: An Optical Module PCB is the internal circuit board of a transceiver (like SFP, QSFP, or OSFP) responsible for converting electrical signals to optical signals and vice versa. Critical Metrics: Signal integrity (insertion loss, return loss) and thermal management are the two.