Patent ID: 9632335
Date: 2017-04-25
CPC Classifications: G02B,G02F,Y10S

Claim:
1. A method for forming an optical device, the method comprising: etching a crystalline silicon substrate disposed on an insulator to form both a right crystalline silicon waveguide and a left crystalline silicon waveguide, wherein the right and left waveguides have respective lower surfaces contacting the insulator; after forming the right and left waveguides, depositing a dielectric material in a vertical gap between the right and left waveguides, wherein the left waveguide is doped a first conductivity type and the right waveguide is doped a second, different conductivity type; depositing a dielectric capping layer on respective upper surfaces of the right waveguide, the left waveguide, and the dielectric material deposited in the vertical gap; and forming a ridge in the dielectric capping layer that at least partially overlaps the dielectric material deposited in the vertical gap, wherein a width of the ridge is equal to or greater than a width of the vertical gap.