Design of GaSb-based monolithic passive photonic devices at wavelengths above 2 µm

Abstract In this paper, we report, for the first time, a theoretical study on passive photonic devices including optical power splitters/combiners and grating couplers operating at non-telecom mid-wave infrared wavelengths. Passive components were designed to operate, in particular, around 2.6 µm monolithic integration with active III-V gallium antimonide material platform. The three popular types of such as directional couplers, multimode interferometer-, Y-branch-couplers theoretically investigated. Based our optimized design rigorous analysis, fabrication-compatible 1×2 splitters less than 0.12 dB excess losses, large spectral bandwidth 50:50 splitting ratio are achieved. For fiber-to-chip coupling, also report an outcoupling efficiency ~29% 2.56 μm 3-dB 80 nm. results represent significant step towards developing complete functional integrated circuits wavelengths.