Patent ID: 7512166

Claim:
A device for controlling optical power of a lightsource and an extinction ratio comprising: a photodetector for detecting the light output by the light source and outputting a first detection signal and a second detection signal; a light source driver for supplying a bias current and a modulation current to the light source; a signal converter for converting the first and second detection signals into voltage signals; and a controller for controlling the bias current based on the first detection signal converted into the voltage signal so that the optical power following the first detection signal may satisfy a first establishing value and controlling the modulation current based on the second detection signal converted into the voltage signal so that the extinction ratio following the first and second detection signals may satisfy a second establishing value, wherein the first detection signal is a signal corresponding to the light output by the light source driven by the bias current, and the second detection signal is a signal corresponding to the light output by the light source driven by the modulation current.