Patent ID: 9696478
Date: 2017-07-04
CPC Classifications: G02B

Claim:
1. An optical device for coupling an external optical signal into a plurality of on-chip channel photonic sub-circuits provided on a substrate, wherein the optical device comprises: a planar waveguide layer on the substrate; a diverging grating coupler configured to couple the external optical signal to the planar waveguide layer, thereby creating a single on-chip diverging optical beam in the planar waveguide layer, wherein the diverging grating coupler is a curved grating coupler; and a plurality of channel waveguides formed in the planar waveguide layer, each channel waveguide of the plurality of channel waveguides comprising a waveguide transition structure having a waveguide aperture oriented towards the diverging grating coupler, wherein for each channel waveguide of the plurality of channel waveguides a position and a width of the waveguide aperture and an angle and a shape of the waveguide transition structure are selected to capture a predetermined portion of the single on-chip diverging optical beam, wherein the waveguide transition structure of a center channel waveguide comprises a center rectangular section, wherein the waveguide transition structure of an outer channel waveguide comprises an outer rectangular section, wherein the center rectangular section and the outer rectangular sections are configured to match an incident field profile of the corresponding predetermined portion of the single on-chip diverging optical beam, and wherein the predetermined portion of the single on-chip diverging optical beam is captured from a slab waveguide region defined in the planar waveguide layer between the diverging grating coupler and the waveguide aperture.