Single-photon Detection Based On The Optical Self-Balancing Technique

With the rise of quantum information technology and the rapid development of ultra-sensitive spectroscopy, single-photon detection, as the key technology, has become an important subject of optoelectronics in the world. In this paper, the near-infrared single photon detection technique based on InGaAs/InP Avalanche Photodiode was introduced. Since the noise of InGaAs/InP APD is serious, such as the dark current, and the afterpulse effect in especial, which restricts the speed of the device in Geiger mode, and affects the performance of single-photon detector. The gated Geiger mode was employed in order to reduce the noise, in which one of the key technology is how to discriminate the weak avalanche signal from the spike noise produced by the gate pulse.We designed and implemented the scheme of optical self-differencing detection. In this method, the electrical signal came from the APD was transferred to the 1550nm light signal by a high speed distributed feedback laser diode. The light signal was then processed in the fiber to realize the self-differencing detection. Finally the week avalanche signal buried in the spike noise was detected and the near-infrared single photon detection was achieved. Owing to precise control in this technique, the spike noise can be effectively suppressed (the suppression of the spike noise was up to 31 dB), which contributed to distinguishing the tiny avalanche signal. The optical self-balancing detector was further used to explore the feature of avalanche in the sub-saturated mode, which illustrated the linear growth relationship between the incident photon number and the avalanche current before the saturation of the avalanche current. It definitely confirmed the capability of photon number resolving with a single InGaAs/InP APD. In addition, we investigated the variation tendency of the photon number resolving characterization with the increase of the avalanche gain. Furthermore, the time-dependent photon number discrimination of InGaAs/InP avalanche photodiode single-photon detector was demonstrated.Besides, we developed the photon number resolving detector based on the Si APD multi-pixel photon counter. And we also accomplished a quantum random bit generator based on the random of photon number in coherent laser with MPPC.