Grating devices on a silicon nitride technology platform for visible light applications

Abstract

We report on the design, fabrication, and evaluation of grating devices, specifically (1) low back-reflection grating couplers and (2) focused Bragg grating mirrors, fabricated on silicon nitride technology platforms for applications in the visible wavelength range. Experiments show that the designed grating couplers exhibit 8 dB-reduced back reflections and a coupling penalty of less than 0.8 dB compared to a conventional grating coupler design. Taking advantage of the 193 nm immersion lithography, focused Bragg gratings are fabricated for the visible wavelengths of 638 nm and 532 nm and over 80% reflectivity is achieved.