Efficient 4.95 μm-8.5 μm dual-band grating coupler with crosstalk suppression capability

In many integrated optics systems, grating couplers are a key component of interfacing the external light source with in-plane photonic devices. Grating couplers with dual-band capability are often desired for expanding the operation spectrum of photonic systems. Here, we propose and theoretically investigate, for the first time, a 4.95 mu m-8.5 mu m dual-band grating coupler on a Ge-on-SOI platform. In addition to conventional structures, Bragg gratings are introduced to two wavelength division directions for crosstalk suppression. With this design, the simulated coupling efficiencies have respectively reached 59.93% and 46.38% for the 4.95 mu m and 8.5 mu m bands. This mid-infrared dual-band grating coupler may be useful for defense and environmental monitoring applications. (C) 2022 Optica Publishing Group under the terms of the Optica Open Access Publishing Agreement

Automated summary

This study proposes a dual-band grating coupler on a Ge-on-SOI platform, covering the 4.95 μm and 8.5 μm bands, with the introduction of Bragg gratings for crosstalk suppression. The simulated coupling efficiencies for the two bands are respectively high, indicating the potential applications in defense and environmental monitoring.