Evanescent Field Coupler Optimized for High Refractive Index Differences (ECHRID)—A Platform for a SOI Photonics Optical Interface

This paper presents the Evanescent field Coupler optimized for High Refractive Index Differences (ECHRID), a proposed new platform for a silicon-on-insulator photonics interface. ECHRID devices are capable of optical performance levels on par with grating couplers and inverted tapers but can be fabricated at much lower cost without the need for high-resolution lithography. Numerical simulations and experimental results are presented that demonstrate average coupling efficiencies between large core injection waveguides and on-chip Si-based waveguides of over 99%, with a flat spectral response over a 120 nm range.