Patent ID: 7627203

Claim:
An integrated optical device, comprising: a substrate; a Mach-Zehnder interferometer provided on the substrate, the Mach-Zehnder interferometer including a first coupler, a second coupler, and first and second waveguide arms extending between the first coupler and the second coupler, wherein the first waveguide arm includes an input section configured to receive light from the first coupler, an output section configured to supply the light to the second coupler, and a thermal tuning section, the thermal tuning section having a path length along which the light propagates extending between the input section and the output section, wherein the thermal tuning section includes a first linear portion and a second linear portion and a bend portion connecting the first linear portion and the second linear portion; and a heater provided on the substrate and in thermal communication with the thermal tuning section of the first waveguide arm, the heater defining and being coextensive with a first region on a surface of the substrate, the first linear portion and second linear portion defining first and second area portions within the first region and the bend portion defining a second region on the surface of the substrate, the second region being outside the first region.