Highly-Efficient Subwavelength Engineered Grating Couplers for Silicon-on-Insulator Waveguides

International audienceWe present experimental results of efficient subwavelength index engineered surface grating couplers, developed in a standard 220-nm SOI substrate. Grating couplers are fabricated using a single full etch or a dual etch process (full etch and 70nm shallow etch). The measured efficiency of -2.2 dB, -2.5 dB, and -0.7 dB are reported for single-etch couplers without and with metal reflector in the near-IR wavelengths. We demonstrate a peak coupling efficiency of -1.3 dB for a novel and flexible dual-etch grating coupler with interleaved deep and shallow etched trenches