基于光波导集成的硅基单光子探测器的研制

Quantum communication is one of the most attactive research fields in the world. The single-photon detector is the key component in the testing system of optical quantum communication. The current free-space-based testing system for optical quantum communication Quantum communication is one of the most attactive research fields in the world. The single-photon detector is the key component in the testing system of optical quantum communication. The current free-space-based testing system for optical quantum communication has some shortcomings, such as big size, high cost and instability. Based on these shortcomings, this project proposal presents a novel silicon-based single photon detector monolithically integrated with optical waveguides. The structure has a potential capability to replace the free-space-based testing system and it has important implications for the future research and applications of optical quantum communications. In this project, we will study the sturcture of the waveguide-integrated silicon-based single photon detector and its performance mechanism. We also study the mechanism about the optical transmission and coupling in the waveguides of the integrated device, the key factors in the process and their impact on the detector’s performances of dark-current and responsivity. Finally, based on the optimization of the device structure and the porcess design, we fabricate and charactrize the waveguide-integrated silicon-based single photo detector on SOI platform.

量子通信是当前国际最热门的研究领域之一，单光子探测器是实现基于单光子传输量子通信系统的核心部件。基于自由空间光学平台的量子通信测试系统带来的庞大体积、高成本和易受干扰的问题，本项目提出一种新型的基于光波导集成的硅基雪崩型单光子探测器。这种新型集成的单光子探测器具有用集成波导结构取代自由空间光路进行光信号传输和探测的潜力，对未来量子通信的研究和应用具有重要意义。本项目拟研究基于SiN光波导集成的横向吸收型硅基雪崩单光子探测器结构及该结构对探测器性能的影响机制、光信号在该集成结构中的传输与耦合机理；研究探测器集成工艺中的关键因素及其对探测器暗电流、光电响应等性能的影响；通过结构与工艺的优化制作可用于单光子探测的波导集成的硅基雪崩单光子探测器芯片，并对该芯片进行测试、分析。

量子光通信是目前研究的热点方向，量子光通信光路的片上集成可以取代复杂的空间光路，在实际应用中具有体积致密、操作简单、成本低等特点。本项目主要研究SiN波导在800nm波段的传输特性以及光纤-SiN波导模斑耦合器在此波段的耦合特性，为SiN波导光路单片集成Si单光子探测器的研究打下集成。我们采用RSOFT光学软件对悬桥结构的光纤-SiN模斑耦合器和SiN纳米线波导进行了仿真设计与结构优化，在优化结构的基础上对版图进行设计并流片制作；经过光学测试，我们得到SiN纳米线波导在800nm波导的TE/TM传输损耗分别为0.07dB/mm和0.06dB/mm；半径为60µm的SiN纳米线弯曲波导的弯曲损耗非常小，完全可以忽略不计；锥形光纤与SiN模斑耦合器的TE/TM耦合损耗分别为-2.06dB/facet和-2.67dB/facet，其耦合效率分别为67%和54%；平头光纤与SiN模斑耦合器的TE/TM耦合损耗分别为-2.50dB/facet和-8.0dB/facet，其耦合效率分别为56%和15%，1dB耦合容差在水平和垂直方向均优于±1.25µm。测试数据完成了本项目的预定目标，其中传输损耗指标达到了国内先进水平，为以后的进一步研究打下了坚实基础。