Re-entrant mirror photodetector with waveguide mode focusing

摘要

A photonic integrated circuit (I/C) includes a focusing sidewall or in-plane surface that redirects and focuses light from a waveguide to a photodetector structure. The focusing includes redirecting an optical signal to a width smaller than a width of the waveguide. The focusing of the light allows the photodetector structure to be outside a waveguide defined by parallel oxide structures. With the photodetector structure outside the waveguide, the contacts can be placed closer together, which reduces contact resistance.

主权项

1. A semiconductor photonic integrated circuit (I/C), comprising:
a waveguide integrated within a semiconductor substrate layer of the I/C, the waveguide horizontally constrained by parallel oxide structures on either side of a semiconductor material of the semiconductor substrate layer, the waveguide having a waveguide width defined by the parallel oxide structures, where an optical signal is to propagate horizontally along the waveguide; a photodetector structure integrated within the semiconductor substrate layer of the I/C, and not within the waveguide defined by the parallel oxide structures; a focusing mirror to focus light of the optical signal to a redirected width smaller than the waveguide width and redirect the light of the optical signal to propagate horizontally along a plane parallel to a surface of the semiconductor substrate layer to exchange the light of the optical signal between the waveguide and the photodetector structure; and multiple photodetector electrical contacts to operate the photodetector structure, the multiple photodetector electrical contacts including a first photodetector electrical contact and a second photodetector electrical contact arranged on opposite sides of the photodetector structure along a line extending athwart a length of the photodetector structure, wherein light redirected by the focusing mirror propagates along the length of the photodetector structure, and wherein a distance between the first photodetector electrical contact and the second photodetector electrical contact is greater than the waveguide width.