摘要 |
A light intensity subtractor according to one aspect of the present invention includes a light subtraction unit, a feedback circuit, a light input port, a first light output port, and a second light output port. The light subtraction unit receives input light through the light input port, outputs first output light to the first light output port, and outputs second output light to the second light output port. The light subtraction unit generates the first output light by reducing the light intensity of the second output light from the light intensity of the input light in accordance with a control voltage. The feedback circuit is connected to the light subtraction unit through the second light output port, and outputs the control voltage in accordance with the light intensity of the received second output light. |