Patent ID: 7164837

Claim:
A method of forming a substantially planar surface of an optical waveguide device, comprising the steps: forming at least one waveguide core portion within at least one cladding portion; the waveguide core portion having an upper surface; the cladding portion having a higher portion over at least the waveguide core portion and a lower portion; forming a patterned sacrificial portion over the lower cladding portion and a portion of the higher cladding portion, leaving a second portion of the higher cladding portion exposed to form an exposed portion of the higher cladding portion; removing at least a portion of the exposed second portion of the higher cladding portion by a selective removal process selective to the patterned sacrificial portion leaving a remnant of the exposed second portion of the higher cladding portion; and planarizing: a) the remnant of the exposed second portion of the higher cladding portion over the waveguide core portion; and b) the lower cladding portion to form a planarized cladding portion coplanar with the upper surface of the waveguide core portion, wherein the waveguide core portion comprises at least one waveguide core embedding within at least another waveguide core.