Hybrid material integration in silicon photonic integrated circuits

Hybrid integration of III-V and ferroelectric materials is being broadly adopted to enhance functionalities in silicon photonic integrated circuits (PICs). Bonding and transfer printing have been the popular approaches for integration of III-V gain media with silicon PICs. Similar approaches are also being considered for ferroelectrics to enable larger RF modulation bandwidths, higher linearity, lower optical loss integrated optical modulators on chip. In this paper, we review existing integration strategies of III-V materials and present a route towards hybrid integration of both III-V and ferroelectrics on the same chip. We show that adiabatic transformation of the optical mode between hybrid ferroelectric and silicon sections enables efficient transfer of optical modal energies for maximum overlap of the optical mode with the ferroelectric media, similar to approaches adopted to maximize optical overlap with the gain section, thereby reducing lasing thresholds for hybrid III-V integration with silicon PICs. Preliminary designs are presented to enable a foundry compatible hybrid integration route of diverse functionalities on silicon PICs.