Grating-Assisted Coupling Between a Low Effective Index Polymer Subwaveguide and a High Effective Index Semiconductor Subwaveguide

In this paper, a leaky-mode directional coupler based on grating-assisted coupling between a semiconductor subwaveguide and a polymer subwaveguide is experimentally demonstrated at wavelengths near 1310 nm. The grating is fabricated at the interface between the semiconductor and polymer materials. The grating period satisfies the phase-matching condition for power exchange between the two nonsynchronous subwaveguides. Experimental and theoretical results show coupling from the semiconductor subwaveguide to the polymer subwaveguide as a function of excitation wavelength.