Patent ID: 9577747
Date: 2017-02-21
CPC Classifications: H01S,H04B,H04J

Claim:
1. A photodetection device comprising: a light reception unit which is disposed behind each of a plurality of light sources that emits signal lights having mutually different wavelengths in a forward direction and receives a backlight emitted backward from each of the light sources; a synchronizing signal generation unit which generates a synchronizing signal serving as an electric signal synchronized in phase with a drive signal for driving each of the light sources; a multiplication unit which multiplies the synchronizing signal generated by the synchronizing signal generation unit and a light reception signal serving as an electric signal obtained by receiving the backlight by the light reception unit; and a light power detection unit which detects power of the signal light by multiplying an integrated value of a multiplication signal obtained by multiplying the synchronizing signal and the light reception signal by the multiplication unit and a power ratio of the signal light to the backlight stored in a predetermined storage unit.