Design and optimization of subwavelength silicon photonics edge coupler for cleaved fibers

Abstract

We propose a fiber-chip edge coupler based on a subwavelength grating in silicon-on-insulator (SOI) platform for coupling to cleaved and high numerical aperture (HNA) optical fibers (mode field diameter of 6.3 μm). Its robustness to fabrication errors and high tolerance to fiber misalignment (±1.5 μm for a 1 dB of excess loss) make it suitable for high-volume production, being a potential candidate for data center applications. Simulation results show a 1 dB bandwidth higher than 200 nm, a polarization dependent loss lower than 0.5 dB, and minimum coupling losses of 1.47 and 1.39 dB for TE and TM modes, respectively, considering a 204 μm-long mode converter.