Patent ID: 8411260

Claim:
An optical device, comprising: a waveguide on a base, the waveguide including an input portion, a light-absorbing portion, and an output portion, the input portion of the waveguide configured to guide a light signal to the light-absorbing portion of the waveguide and being partially defined by a light-transmitting medium that includes a top side that defines a portion of the input portion of the waveguide, the light-absorbing portion of the waveguide configured to absorb a portion of the light signal and to guide a transmitted portion of the light signal to the output portion of the waveguide, and the light-absorbing portion of the waveguide being partially defined by a light-absorbing medium that is different from the light-transmitting medium and a bottom side of the light-absorbing medium being between the base and a top side of the light-absorbing medium, the top side of the light-transmitting medium being less far from the base than the top side of the light-absorbing medium but further from the base than the bottom side of the light-absorbing medium, the output portion of the waveguide configured to receive the transmitted portion of the light signal from the light-absorbing portion of the waveguide and to guide the transmitted portion of the light signal away from the light-absorbing portion of the waveguide, and the output portion of the waveguide and being partially defined by the light-transmitting medium; and a monitor positioned on the base and configured to monitor absorption of the absorbed portion of the light signal.