High index-step grating fabrication using a regrowth-over-dielectric process

Abstract

An optical device () including a first semiconductor layer () on which is deposited a dielectric layer that is patterned and etched to form dielectric strips () as part of a diffraction grating layer. Another semiconductor layer () is grown on the first semiconductor layer () between the dielectric strips (), resulting in alternating dielectric sections () and semiconductor sections. In an alternate embodiment, a dielectric layer is deposited on a first semiconductor layer (), and is patterned and etched to define dielectric strips (). The semiconductor layer () is etched to form openings () between the dielectric strips (). Another semiconductor material () is grown within the openings () and then another semiconductor layer () is grown over the entire surface after removing the dielectric strips (). Either embodiment may be modified to provide diffraction grating with air channels ().