Unlike conventional PCBs, those designed for optical modules operate at the intersection of extreme electrical performance, stringent thermal constraints, and microscopic mechanical tolerances. The Printed Circuit Board (PCB) at the heart of these modules is no longer a simple substrate but a highly engineered system. Designing and producing these complex PCBs presents formidable challenges, requiring a convergence of disciplines—from high-frequency signal integrity and advanced thermal. Traditional architectures that rely on pluggable optical modules are hitting physical limits in signal attenuation, power, and port density. Data rates range from 155 Mbps to 6 Gbps and even up to 10 Gbps.