Patent ID: 7308160

Claim:
An optical phase-shifter device comprising: a waveguide, wherein the waveguide includes: an optical mode portion, the optical mode portion allowing a light beam to pass there through, and a doped region, wherein the doped region contains free charge carriers and overlaps the optical mode portion; and a semiconductor structure, wherein the semiconductor structure includes: a first highly doped region, wherein the first highly doped region is arranged proximate to the doped region and is doped with a polarity opposite to that of the doped region, a second highly doped region, wherein the second highly doped region is doped with a polarity similar to that of the doped region, and an intervening region, wherein the intervening region is substantially free of dopants and is arranged between the doped region and the second highly doped region so as to prevent contact between the doped region and the second highly doped region, wherein the semiconductor structure controls the free charge carrier content of the doped region in accordance with an external electrical control potential applied across the first and second highly doped regions.