基于InGaAs/InP APD的高速近红外单光子探测系统研究

InGaAs/InP avalanche photodiode (APD) based single-photon detection system is a reliable and practical solution for ultraweak optical detection in the near infrared, which has been extensively applied in many different fields, particularly in quantum cryptography and quantum communication system. However, due to the limits of quenching techniques,the saturated count rate of conventional InGaAs/InP single-photon detector system is only around hundreds of kHz. That significantly limits the performance improvement of quantum communication system in terms of secure communication distance and final key rate. Therefore, developing high-speed InGaAs/InP single-photon detector system with high saturated count rate is urgently required, which is also the key point in the field of quantum cryptography presently. The key scientific question of high-speed single-photon detection is how to effectively suppress the afterpulsing effect while effectively extract weak avalanche signals.In this project, we will study the mechanism of high-speed gating theoretically and experimentally. With the technique of sine wave gating and filtering, we can implement high-speed single-photon detection and further develop a fully integrated and compact InGaAs/InP single-photon detector system with GHz frequency gating. Our project will definitely pave the way to further develop the next generation of high-speed quantum cryptosystem in the future.

基于InGaAs/InP雪崩光电二极管的单光子探测系统是进行近红外波段弱光探测的主要选择，在许多领域中得到了广泛的应用，尤其是量子密码和量子通信系统中的关键性器件。然而由于技术上的限制，采用传统方法的单光子探测系统计数率仅在几百kHz，这已经严重限制量子通信系统性能提升比如安全距离、最终密钥率等。因此，研发高速高计数率的InGaAs/InP单光子探测系统刻不容缓，这是目前量子通信领域激烈国际竞争的技术制高点。高速单光子探测研究中一个需要解决的关键科学问题是如何在有效抑制afterpulse效应的同时能够有效提取微弱雪崩信号。在本项目我们将从理论和实验上研究高速门控的机理，采用正弦门控与滤波技术实现高速单光子探测，在此基础上研制出集成化、小型化GHz频率的InGaAs/InP单光子探测系统原型样机，为未来研发下一代高速量子通信系统奠定坚实的技术基础。

单光子探测器是进行超微弱光探测所必不可少的工具。在量子通信系统中，单光子探测器的工作频率直接决定了量子通信的通信速率和通信距离。在本项目的支持下，通过对单光子雪崩光电二极管雪崩过程中载流子动力学等机理的研究，发展正弦门控、集成滤波、后脉冲概率精确标定等核心技术，成功研制出国际上首个全集成1.25 GHz InGaAs/InP单光子探测器，圆满完成项目的研究目标。随后进一步研制出集成化四通道1.25 GHz门控单光子探测器。该探测器可以大幅提升现有量子通信系统的性能。. 2016年，共有580台基于高速门控技术的单光子探测器在国家量子保密通信“京沪干线”技术验证及应用示范项目中得到部署，是迄今为止国际上唯一规模化应用于量子通信网络的单光子探测器。此外，本项目的高速单光子探测技术也在量子雷达、量子随机数发生器等领域得到了应用。. 在本项目的执行期间，共在国际知名期刊如Light: Science & Applications、Optica、Applied Physics Letters、Review of Scientific Instruments发表与项目研究目标相关的SCI论文8篇，其中6篇项目负责人为通讯作者。共授权/受理发明专利5项，项目负责人均为第一发明人。