Photon detector, a quantum cryptography communication apparatus using the same, and the photon detection method

摘要

PPROBLEM TO BE SOLVED: To prevent an excessive bias voltage generated immediately after dead time is ended and eliminate incorrect detection. PSOLUTION: A photon detector having an APD for detecting photon includes a gate pulse generator 2' and a bias tee 5 for applying a sum of a periodic gate pulse 3c in response to the estimated time of arrival of the photon and a DC voltage from a DC voltage source 6 to an APD 8 as an APD bias voltage 7a, and a dead time signal generator 13 for allowing an output of the gate pulse 3c to be resumed after a predetermined time is elapsed by suppressing the output of the gate pulse 3c during a predetermined period of time immediately after the photon is detected by the APD 8. Also, the gate pulse 3c includes positive and negative gate pulses where the positive gate pulse 3a and negative gate pulse 3b are combined. PCOPYRIGHT: (C)2011,JPO&INPIT