PHOTON DETECTOR HAVING COUPLING CAPACITOR

摘要

PURPOSE: A optical detector including the coupling capacitor is provided to control the movement characteristic deviation of each detectors easily by using the coupling capacitor and operating each avalanche photo diode with different bias voltage. CONSTITUTION: The optical detector(100) having a coupling capacitor includes: an avalanche photodiode(APD); a bias circuit(110); a detection circuit(120); and a coupling capacitor(Cc). The bias circuit offers the bias voltage(Vb) to one end of the avalanche photo diode. The detection circuit is connected to the other end of the avalanche photo diode and detects the photo current generated in the avalanche photo diode. The coupling capacitor is first of all connected to the fist or the other end of avalanche photo diode. The coupling voltage for driving the avalanche photo diode to the Geiger mode is offered. The coupling capacitor is formed into the fixed type. The size of the coupling voltage is varied according to the size of the overdrive voltage(Vod) offered to the coupling capacitor. The bias voltage is lower than the break down voltage of the avalanche photo diode.