Patent ID: 8853809

Claim:
A photodetector comprising: an optical element for transmitting light therethrough along a predetermined direction and modulating the light, the optical element comprising a structure having first regions and second regions periodically arranged with respect to the first regions along a plane perpendicular to the predetermined direction; wherein the first and second regions have respective refractive indexes different from each other, and properties of transmitting the light therethrough; the light having no electric field component in the predetermined direction is modulated such as to attain an electric field component in the predetermined direction; a semiconductor multilayer body arranged on the other side opposite to one side in the predetermined direction with respect to the optical element and adapted to generate a current due to an electric field component in the predetermined direction in the light transmitted through the optical element; a first contact layer formed on a surface on the one side of the semiconductor multilayer body; and a second contact layer formed on a surface on the other side of the semiconductor multilayer body.