Coupling Efficiency Of Monolithic, Waveguide-integrated Si Photodetectors

摘要

A waveguide-integrated photodetector provides a small-footprint, low-capacitance design that overcomes the bandwidth-efficiency trade-off problem of free space optics. High performance silicon devices are critical to the emergence of electronic-photonic integrated circuits on the complementary metal oxide semiconductor platform. We have fabricated vertical p-i-n silicon photodetectors that are monolithically integrated with compact silicon oxynitride channel waveguides. We report over 90% coupling efficiency of 830 nm light from the silicon oxynitride (SiO_xN_y) channel waveguide to the silicon photodetector. We analyze the dependence of coupling on waveguide index by comparing coupling from low index-contrast waveguides and high index-contrast waveguides.