Coupling performance and fabrication method of a waveguide grating coupler with non-uniform duty ratio

초록

We proposed a novel grating design of an out-of-plane coupler with non-uniform duty ratio operating at a wavelength of 1.55 μm for the highly efficient coupling from a waveguide to an optical fiber. In order to evaluate the coupling performance, the diffracted output beam profile and the focusing performance due to the variations of duty ratio configuration were investigated by a 2D Bloch-wave analysis. In addition, a simple fabrication method was proposed to realize the grating by the Near-Field Holographic lithography system with variable aperture unit.