Desing of grating couplers for submicron optical waveguides

Optical coupling gratings are strategic components of integrated optics that allow the interaction of a laser signal with optical interconnects, integrated photonic microdevices and biosensors. In this work, the design of binary and sinusoidal type coupling gratings for Al2O3/SiO2/Si submicron guides operating in the visible (633 nm) and infrared (1550 nm) is presented herein. In particular, the coupling efficiency is analyzed as a function of the main design parameters: waveguide thickness, period, etch depth and incidence angle. The results indicate that coupling efficiencies of 21 and 15 percent and decoupling efficiencies of 25 and 22 percent can be obtained for binary and sinusoidal gratings, respectively, at a wavelength of 1550 nm; coupling efficiencies of 7.8 and 7.6 percent and decoupling efficiencies of 53 and 34 percent can be obtained for a wavelength of 633 nm. The proposed designs have potential applications for the fabrication of integrated circuits.