Light Sources for Quantum Communication in the 1300 nm Spectral Range

为长距离光纤量子通信实现新型、电信兼容的光电器件是本项目的中心目标。关键技术解决了基于单量子点的单光子源（SPSs）的电和光激发以及在~1300 nm波长范围内的先进垂直腔表面发射激光器（VCSELs）。该项目的总体目标是将这两项关键技术结合起来，即实现由电泵浦VCSEL共振驱动的电信o波段（1.3 μ m）中具有不可分辨光子发射的高效单光子源。这为仅基于半导体技术的紧凑实用的SPSs铺平了道路。量子点结构将生长在分布式布拉格反射器（DBRs）上，并在其上沉积介电多层结构以形成微腔。电介质结构将进一步横向图案化，以允许单光子在单模波导或标准单模光纤中进行简单高效的耦合（bbb80 %）。将采用独特的原位低温电子束光刻技术来定义微腔的基础平台，以适当地将它们对准单个预选的量子点，以获得最佳的器件性能。对于单量子点的共振高速激发，将实现1300 nm波长范围内的高速vcsel。因此，基于gaas的单片和基于inp的晶圆融合vcsel技术都将得到应用和测试，以获得卓越的性能。制备的结构将通过量子光学实验进行研究和评估，以确定与预期应用相关的最重要特性，如发射动力学/速率、光子提取效率、单光子发射纯度和单光子不可分辨性。来自德国和俄罗斯的合作伙伴双方长期以来互补性专业知识的协同作用，为这一雄心勃勃的方法取得成功提供了必要的基础，从而促进了量子信息处理在电信波长范围内的实际应用。

The realization of novel and telecom-compatible optoelectronic devices for long-distance fiber-based quantum communication is the central goal of this project. The key technologies address single-QD-based single-photon sources (SPSs) for both electrical and optical excitation and advanced vertical-cavity surface-emitting lasers (VCSELs) in the ~1300 nm wavelength range. The overarching goal of the project is the combination of both key technologies, namely the realization of a highly-efficient single-photon source with indistinguishable photon emission in the telecom O-band (1.3 µm) that is resonantly driven by an electrically-pumped VCSEL. This paves the way for compact and practical SPSs based solely on semiconductor technology.The QD structures will be grown on top of distributed Bragg reflectors (DBRs) and dielectric multilayer structure will be deposited on top to form a microcavity. The dielectric structure will be further laterally patterned to allow for simple and highly-efficient coupling (>80%) of single photons into single-mode waveguides or standard single-mode fibers. Unique In-situ low-temperature electron-beam lithography will be applied to define the microcavitys’ base-mesas to properly align them to single pre-selected QDs for optimal device performance. For the resonant high-speed excitation of the single QDs high-speed VCSELs in the 1300 nm wavelength range will be realized. Therefore, both GaAs-based monolithic and InP-based wafer-fusion VCSEL-technologies will be utilized and tested for superior performance. The fabricated structures will be investigated and evaluated by quantum-optical experiments to determine the most important properties with respect to the envisaged applications like emission dynamics/rates, photon-extraction efficiency, purity of single-photon emission, and indistinguishability of the single photons.The synergy of the complementary long-standing expertise of both partners from Germany and Russia provides the necessary basis to succeed in this ambitious approach to foster real applications in quantum information processing in the telecom wavelength regime.