InGaAs/InP 单光子探测器研究进展(特邀)

Single photon detectors are the most sensitive devices in weak light detection area. In the near-infrared region, InGaAs/InP single photon avalanche diodes are widely used in various fields due to their excellent overall performance, small size, low cost and ease of operation. Driven by the rapid development of quantum communication and LiDAR in the last decade, the device performance of single photon detectors and its relevant avalanche quenching techniques have been improved steadily. This paper provides a comprehensive review of the development of InGaAs/InP single photon detectors over the past decade, including structural optimization and mechanism research of single photon avalanche diodes, as well as the latest readout technologies for gated and free-running mode single photon detectors. Finally, we will give an outlook for this field. For near-infrared single-photon detection, the mainstream devices include photomultiplier tubes, superconducting single-photon detectors, upconversion single photon detectors and semiconductor single-photon detectors. Photomultiplier tubes have the advantages of high gain and large photosensitive area, but their detection efficiency is limited by the efficiency of photoelectron generation by the photocathode. Upconversion single-photon detectors utilize the frequency up-conversion of nonlinear crystals to transfer single photons from the near-infrared band to the visible light band. However, this method requires a strong pump laser and high-efficiency narrowband filtering technology to remove conversion noise, resulting in a narrow spectral response, which poses challenges for its practical application. Superconducting single-photon detectors are divided into superconducting Transition Edge Sensors (TES) and Superconducting Nanowire Single-Photon Detectors (SNSPDs) . TES utilizes the superconducting phase transition induced by the thermal effect of absorbed photons for detection, achieving extremely high detection efficiency. However, TES suffers from significant time jitter and requires operation at 100 mK, necessitating complex cooling equipment. SNSPDs utilize the change in current density caused by an incident single photon for detection, exhibiting extremely high detection efficiency, extremely low dark count rate, extremely low time jitter, and no afterpulse effect. However, their operating temperature range of 4 K also limits its large-scale practical application. Compared to previous single-photon detectors, semiconductor single-photon detectors offer advantages such as low cost, small size, ease of operation, and excellent overall performance, making them the preferred solution for various practical applications, including metropolitan quantum communication. A semiconductor single-photon detector consists of Single-Photon Avalanche Diodes (SPADs) and a Readout Integrated Circuit (ROIC), both of which significantly impact the detector's performance. The SPAD operates in Geiger mode, where the reverse bias voltage is higher than its breakdown voltage. When an incident single photon is absorbed in the absorption layer, it generates charge carriers, which then enter the multiplication layer under the influence of an internal electric field. Accelerated by the strong electric field in the multiplication layer, these charge carriers collide with atoms, ionizing and potentially triggering an avalanche effect, generating an observable macroscopic avalanche current. The readout circuit reads out the avalanche current signal and promptly quenches it to prevent damage to the device, ensuring it can be used for subsequent detections. Semiconductor single-photon detectors can be divided into gated mode and free-running mode according to their operating modes. The design of the readout circuit is very different for different operating modes. At present, the types of semiconductor single-photon detectors used in the near-infrared band include InGaAs/InP, InGaAs/ InAlAs and Ge-on-Si SPADs, among which InGaAs/InP single-photon detectors have the best overall performance and are the most widely used devices at present. Research on InGaAs/InP single-photon detection began in the mid-1990s. Initially, commercially available Geiger-mode InGaAs/InP APDs were used for optical communication. However, due to their high dark count rate, InGaAs/InP APDs had to be cooled to below 100 K and operated in low-speed gated mode. In the 2000s, the rise of quantum communication became another strong driving force for the development of InGaAs/InP single-photon detection research. People optimized the structure of Geiger-mode InGaAs/InP SPADs and invented Negative Feedback Avalanche Diodes(NFADs) for free-running mode. At the same time, basic avalanche readout techniques, such as Sine-Wave Gating (SWG), capacitance balancing and self-differential techniques, were also developed during this period. However, InGaAs/InP single-photon detectors still face the problems of low photon detection efficiency and high noise. Over the past decade, research on InGaAs/InP single-photon detectors has primarily focused on improving performance metrics, particularly Photon Detection Efficiency (PDE) and Dark Count Rate (DCR) . Through improvements in structural design and fabrication techniques, combined with research into the physical mechanisms of avalanche diodes, the performance of InGaAs/InP SPADs has been significantly optimized. For synchronous photon detection applications such as quantum communication, researchers have optimized various parameters of high-frequency gated single-photon detectors and proposed novel gated readout circuits to achieve higher operating frequencies and greater integration. For asynchronous photon detection, various methods have been developed to achieve free-running modes for InGaAs/InP SPADs, including NFADs, active quenching circuits, and gated free-running operations.