Packaging Process for Grating-Coupled Silicon Photonic Waveguides Using Angle-Polished Fibers

A novel process for fiber-packaging submicrometer silicon waveguides is presented. The process uses fibers polished at an angle to reflect light between a horizontal core and the slightly off-vertical input and output path of a grating coupler. The necessity for a reflective coating on the fiber facet is overcome through the use of total internal reflection and a novel technique of epoxy distribution based on capillary action. Simulations of alignment tolerance are presented, along with measurements confirming the applicability of passive alignment. A peak coupling efficiency within 0.2 dB of the theoretical maximum for the grating coupler is achieved.