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.