A novel single-photon detector based on capacitance-balancing technique

Abstract

A gated InGaAs/InP single-photon detector based on a novel capacitance balancing technique was demonstrated. The single-photon detector is based on a gated InGaAs/InP avalanche photodioe. A quantum efficiency of 10% at 1550nm was obtained with a dark count probability per gate of 1.82×10 and an afterpulsing probability of 3.6% at a detection rate of 100 MHz. Moreover, compared with traditional capacitance balancing technique, our scheme can reduce dark count probability obviously. Introduction Near infrared single-photon detectors (SPDs) are widely used in many fields, such as quantum secure communication, astronomy, and ultrasensitive spectroscopy. The InGaAs/InP avalanche photodiode (APD) has been the most practical device for SPDs at telecommunication wavelength[1]. Since a photo-excited carrier grows into a macroscopic current output via the carrier avalanche multiplication in an APD operated in the Geiger mode, a single photon can be detected efficiently. However, some carriers trapped in the APD are subsequently emitted, and trigger additional avalanches that cause erroneous events. The InGaAs/InP APD in Geiger mode has a particular high probability that these so called “afterpulses” occur. Therefore, the InGaAs/InP APD is usually operated in the gated mode in which the gate duration (gate-on time) is generally set to a few nanoseconds. Then the interval between two consecutive gates is set to more than the lifetime (in orders of microseconds) of the trapped carriers so that the afterpulse is suppressed. The alternative SPDs at telecommunication wavelengths are frequency-upconversion-assisted Si-APD (upconversion detector) and a superconducting single-photon detectors (SSPD). Although these SPDs can be operated with greater voltages than gigahertz clock systems, they have drawbacks that make them difficult to apply to practical QKD systems. The upconversion detectors suffers from background noise counts with high detection efficiency, while the SSPD requires cryogenic below 4K. Thus far,several techniques, such as self-differencing technique[2], and sinusoidal gating technique[3], have been invented for InGaAs/InP single-photon avalanche photodioses(SPADs) in the gated Geiger mode, increasing the working speed over GHz. With these methods, SPADs can sense much weaker photon-induced avalanches at a high speed with good performance. However, it is quite difficult to change the gating frequencies of these SPADs, limiting their applications. Here, we propose the capacitance-balancing technique to solve the problem, easily tuning the gating frequencies without changing any state of the SPAD. At a detection rate of 200 MHz, we obtained a single photon detection efficiency of 10% with an afterpulse probability of 3.6% and a low dark count rate (1.82×10 per pulse). These make the device suitable for quantum secure communication, which requires that the bit error rate is less than 5%. 4th International Conference on Machinery, Materials and Computing Technology (ICMMCT 2016) © 2016. The authors Published by Atlantis Press 726