Integrated photonic coupler

摘要

The present invention relates to an integrated photonic device comprising a photonic substrate, and an integrated waveguide provided in or on this substrate. The waveguide is adapted for conducting radiation of a predetermined wavelength. The device further comprises a sub-wavelength grating optically connected to the waveguide, which provides a first periodic variation of the refractive index in at least one first spatial direction. The device also comprises a diffracting grating arranged over the sub-wavelength grating for coupling radiation of the predetermined wavelength in and/or out of the integrated waveguide via the sub-wavelength grating. The diffracting grating provides a second periodic variation of the refractive index in at least one second spatial direction. The first periodic variation has a first pitch that is less than half of the predetermined wavelength, while the second periodic variation has a second pitch that is at least half of the predetermined wavelength.

主权项

1. An integrated photonic device comprising:
a substrate; an integrated waveguide formed on the substrate, the integrated waveguide being configured to conduct light of a predetermined wavelength; a sub-wavelength grating integrated in the integrated waveguide, the sub-wavelength grating providing a first periodic variation of a refractive index in the integrated waveguide in at least one first spatial direction, wherein the first periodic variation has a first pitch that is less than half of the predetermined wavelength; and a diffracting grating for at least one of (1) coupling light of the predetermined wavelength into the integrated waveguide via the sub-wavelength grating or (2) coupling light of the predetermined wavelength out of the integrated waveguide via the sub-wavelength grating, the diffracting grating (i) providing a second periodic variation of the refractive index in at least one second spatial direction, wherein the second periodic variation has a second pitch that is at least half of the predetermined wavelength and (ii) being at least one of: (a) arranged above the sub-wavelength grating with respect to the substrate; or (b) partially etched in the sub-wavelength grating,
wherein the sub-wavelength grating is etched into the integrated waveguide to a first depth with respect to the substrate and the diffracting grating is partially etched into the sub-wavelength grating to a second depth with respect to the substrate,wherein the second depth is less than the first depth with respect to the substrate.