Light monitor configured to tap portion of light signal from mid-waveguide

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, the light-absorbing medium has lateral sides that each extends between a top side and a bottom side of the light-absorbing medium, the bottom side being between the base and the top 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, the monitor including field sources that are each configured to serve as a source of an electrical field in the light-absorbing medium,
• the field sources each contacting one of the lateral sides and the lateral sides that are contacted by the field sources being on opposing sides of the light-absorbing medium, and
• 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.