Coupling light between an optical fiber and photonic IC is a challenging task. A large mismatch in propagation constant and size make traditional end-fire coupling very inefficient.  The grating coupler is a versatile scheme for coupling light to a submicron waveguide where light can be vertically coupled from an optical fiber into a waveguide. Though the scheme is simple and versatile, achieving larger bandwidth and high coupling efficiency simultaneously is yet to be achieved. Our primary focus is to develop coupling device that has high coupling efficiency with large operational bandwidth and also develop novel coupling schemes for a wide range of material platform.