Analysis of vertical coupling between a 2D photonic crystal cavity and a hydrogenated-amorphous-silicon-wire waveguide

We present an efficient means of light extraction from two-dimensional photonic crystal (2D PC) cavities with SiO2 cladding. We propose a vertically coupled system consisting of a 2D PC cavity and a hydrogenated-amorphous-silicon (a-Si:H)-wire waveguide, which we theoretically investigate using the 3D finite-difference time-domain method. Light can be extracted with an efficiency of greater than 95% to both output ports of the a-Si:H-wire waveguide or extracted with an efficiency of greater than 90% to a single output port of the a-Si:H-wire waveguide with a reflector.

► We have investigated the extraction of light from two-dimensional photonic crystal (2D PC) cavities with SiO2 cladding. ► The extraction of light with an efficiency of greater than 90% can be achieved. ► The light is efficiently extracted from the cavity to hydrogenated-amorphous-silicon (a-Si:H)-wire waveguide. ► Although SiO2 cladding is used (not air), the attractive system can be achieved.