Compact non-volatile multilevel Sb2Se3 electro-optical switching in the mid-infrared group-IV-photonics platform

• DOI: 10.1016/j.optlastec.2024.111005
• Publication Date: 2024-04-12T15:52:53Z
• Authors: Richard Soref; Francesco De Leon...; Martino De Carlo; Vittorio M.N. Pas...
• Keywords: Bistability; Switching time

This theoretical modeling and simulation paper presents designs projected performances of two non-volatile, broadband, on-chip 2 × electro-optical switches based upon the germanium-on-insulator (GeOI) photonic-electronic platform operating at 2.5 µm mid-infrared wavelength. These compact devices facilitate large-scale integration on a "monolithic wafer" where all components are made group-IV semiconductors. The two-waveguide directional coupler (DC) Mach-Zehnder interferometer (MZI). A thin-film graphene Joule-effect micro-heater is assumed planarized GeOI device to change phase (reversably) DC-slot-embedded Sb2Se3 phase-change material (PCM) from crystalline amorphous. MZI has this PCM within its slotted-arm waveguides. Simulations show high-performance bistable or multi-stable cross-bar switching in both devices. DC an active coupling length 17 µm, 130 nm gap, footprint 5 x 31 µm. bandwidth 30 over wavelength range cross bar insertion losses IL less than 0.3 dB, optical crosstalk −15 dB. Results for crossbar attained with 7.8 µm-length slot 51 switch footprint. Stable, multi-level via partial amorphization. Thermal shows that careful control voltage-pulse amplitude V applied (rectangular pulse duration 500 ns) can give 32 levels, example, using 6.18 7.75 Volts. Multi-level shown also PCM-based ring resonators.