Finishing of Optical Module PCBs
Common techniques include copper paste via filling, embedded copper blocks, plated-through holes, or designing PCBs as ELICs (Electrolytic-Laminated Interconnect Circuit) by stacking blind vias into columnar structures for heat dissipation. The Printed Circuit Board (PCB) at the heart of these modules is no longer a simple substrate but a highly engineered system. It consists of a photoelectric converter, driver circuit, receiver circuit, and control circuit. 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. ❑ This mSAP example module plug board including DC block at 56 GHz for 113 GBd module has a loss of just 2. 6 dB! Conventional construction and mSAP losses are about the same but conventional PCB will have additional degradation not reflected in the loss.
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