Broadband tunable basic units for nonvolatile field programmable photonic gate array

Abstract

Field programmable photonic gate arrays (FPPGAs) use 2×2 tunable basic units (TBUs) interconnected as a mesh to achieve various functionalities on the same chip. It is desirable to have TBUs that can retain the state without power and function over a broad bandwidth. Different TBU structures and materials are compared in this work to design a suitable nonvolatile broadband device. An optical phase change material (O-PCM) based Mach–Zehnder interferometer provided the required nonvolatile TBU with a high bandwidth, low insertion loss, and low crosstalk. Among the various O-PCM materials, Sb2S3 provided the lowest insertion loss of <1dB and a low crosstalk of <−25dB. The proposed TBU can enable a low-power FPPGA with a smaller footprint and broader bandwidth compared to their volatile thermo-optic or electro-optic counterparts.