Photonic integration: Si or InP substrates?

A brief review of recent progress in photonic integrated circuits (PICs) is presented. By examining Moore's Law and the roadmap of conventional electronic ICs, valuable lessons in host material selection for PICs are discussed. Finding a primary host material for integration is necessary and vital to the success of the PIC industry. Initial success has been achieved in both InP-based and silicon-based commercial PICs; however, we believe that cost and performance may select silicon as the primary host material, with the urgency to deploy optical interconnects on Si electronic ICs as one of the main reasons. A recently introduced hybrid silicon evanescent platform and devices and silicon/germanium APDs are reviewed as examples to understand the viability of silicon PICs and lead to an understanding of a possible roadmap to next generation large-scale PICs.