Multi-material heterogeneous integration on a 3-D photonic-CMOS platform

Abstract

Photonics has been one of the primary beneficiaries of advanced silicon manufacturing. By leveraging mature complementary metal-oxide-semiconductor (CMOS) process nodes, unprecedented device uniformity and scalability have been achieved at low costs. However, some functionalities, such as optical memory, Pockels modulation, and magnetooptical activity, are challenging or impossible to acquire on group-IV materials alone. Heterogeneous integration promises to expand the range of capabilities within silicon photonics. Existing heterogeneous integration protocols are nonetheless not compatible with active silicon processes offered at most photonic foundries. In this work, we propose a novel heterogeneous integration platform that will enable wafer-scale, multi-material integration with active silicon-based photonics, requiring zero change to the existing foundry process. Furthermore, the platform will also pave the way for a class of high-performance devices. We propose a grating coupler design with peak coupling efficiency reaching 93%, an antenna with peak diffraction efficiency in excess of 97%, and a broadband adiabatic polarization rotator with conversion efficiency exceeding 99%.