新型光纤耦合声光调制器的理论和实验研究

With the rapid development of information technology, the secure transfer of information transmission has been attracted more and more attention. Because of its high security advantages, quantum communication has great application value in the field of the information security. In order to reduce the required storage time for entanglement and to enhance probability for generating the entangled atom-photon pair, the multiplexed quantum repeater protocols has become a research focuse. It has been proved that, by using an entangled photon collector with feedforward control, this probability can be enhanced without introducing extra multiexcitation noise. In this project, the theoretical and experimental study of a new optical fiber coupled acousto optic modulator is proposed. By means of reducing optical loss and designing phase compensation module, the new fiber coupled acousto optic modulator can realize Arbitrary polarized light passing through the device with high transmittance and polarization remained, so that the entanglement and entanglement generation rate are not affected. And the new modulator realizes the entanglement collection function using the feedforward control in the multiplexed quantum repeater. The combination of a number of the new modulators can also enhance the probability of entanglement, without introducing extra multiexcitation noise. The new type of fiber coupled acousto optic modulators will be widely applied, not only for quantum communication, but also for pulsed fiber lasers, fiber amplifiers, pulse collectors and other fields. The transformation of science& technology achievement can also serve the needs of the relevant domestic organizations for fiber coupled acousto optic modulator.

信息化快速发展的今天，信息的安全传输日益受到人们的关注。量子通信以其高安全性的优势，在信息安全领域有着重大的应用价值。为减少纠缠所需存储时间、增强光与原子纠缠产生率，复用的量子中继方案成为研究热点。研究证实，前馈控制的纠缠光子采集器能在不引入额外多光子噪声的前提下，增强纠缠产生率。本项目拟进行新型光纤耦合声光调制器的理论和实验研究。新型光纤耦合声光调制器通过降低其光学损耗、设计相位补偿模块等手段，可以实现任意偏振光经过该器件透过率较高且偏振保持不变，从而不影响纠缠度和纠缠产生率。利用该新型器件可以实现复用量子中继的纠缠反馈采集功能。通过多个该新型器件的组合，可以实现纠缠产生率的增强，同时没有引入额外的多光子激励噪声。此类新型光纤耦合声光调制器应用广泛，不仅适用于量子通信，而且适用于脉冲光纤激光器、光纤放大器、脉冲采集器等领域。该器件的成果转化，也可以服务于国内有关单位对此类器件的需求。

量子通信中，为减少纠缠所需存储时间、增强光与原子纠缠产生率，可利用前馈控制的纠缠光子采集器能在不引入额外多光子噪声的前提下，增强纠缠产生率。本项目以声光器件入手，研究影响光与原子纠缠的因素，并主要通过声光器件的改进实现光与原子纠缠率的提升、实现长寿命量子记忆的光与原子纠缠态。按照计划，课题组通过三年的研究工作，实验上重新建立并完善了铷原子磁光阱系统，优化了轴向磁场及补偿地磁场线圈设计降低了磁场梯度，获得了高光学厚度冷原子系综。并通过减小采集光路和写读光光路的角度延长了自旋波波长，在冷原子系综中获得毫秒量级的光与原子纠缠。实验结果显示器件提升后在初始恢复信号时刻Bell参量可以达到2.5，在1.2ms时仍能达到2.3。完成了项目计划内容，获得了预期是研究成果。项目执行期间共发表学术论文7篇，其中包括Phys. Rev. A, Optics Express等SCI高区论文4篇；授权实用新型专利1项。该实验结果适用于脉冲光纤激光器、光纤放大器、脉冲采集器等领域，在量子信息通信以及量子计算中有重要的潜在应用价值。