Programmable linear optical processors (LOPs) can have widespread applications in computing and information processing due to their capabilities to implement reconfigurable on-chip linear transformations. A conventional LOP that uses a mesh of Mach-Zehnder interferometers (MZIs) requires $2N+3$ stages of phase shifters for $N \times N$ matrices. However, it is beneficial to reduce the number of phase shifter stages to realize a more compact and lower-loss LOP, especially when long and lossy electro-optic phase shifters are used. In this work, we propose a novel structure for LOPs that can implement arbitrary matrices as long as they can be realized by previous MZI-based schemes. Through numerical analysis, we further show that the number of phase shifter stages in the proposed structure can be reduced to $N+2$ and $N+3$ for a large number of random dense matrices and sparse matrices, respectively. This work contributes to the realization of compact, low-loss, and energy-efficient programmable LOPs.
Programmable Non-Hermitian Synchronization of Light on a Silicon Photonic Processor
KTH Royal Institute of Technology（瑞典皇家理工学院）；University of Michigan（密歇根大学）；University of Vaasa（瓦萨大学）；Institute of Science Tokyo（东京科学大学）；Huazhong University of Science and Technology（华中科技大学）
Ising accelerator with a reconfigurable interferometric photonic processor
Universitat Politècnica de Valencia（瓦伦西亚理工大学）；Queen’s University（女王大学）；IPronics Programmable Photonics S.L（IPronics可编程光子有限公司）；Indian Institute of Technology Delhi（德里印度理工学院）
Universal Neural Network Based Calibration and Control of Programmable Classical and Quantum Photonic Integrated Processors
Centre de Nanosciences et de Nanotechnologies, CNRS, Université Paris-Saclay（纳米科学与纳米技术研究中心，法国国家科学研究中心，巴黎萨克雷大学）；Centre for Nanophotonics, Department of Physics, Engineering Physics and Astronomy, Queen’s University（量子大学纳米光子学中心）；IPronics Programmable Photonics S.L（IPronics可编程光子有限公司）；Photonics Research Lab, iTEAM, Universitat Politècnica de València（瓦伦西亚理工大学iTEAM研究所光子研究实验室）
Compact and programmable large-scale optical processor in free space
Scuola Superiore Meridionale（南方高等学院）；University of Ottawa（渥太华大学）；Nexus for Quantum Technologies（量子技术联盟）；National Research Council of Canada（加拿大国家研究委员会）；Università degli Studi di Napoli Federico II（那不勒斯费德里科二世大学）；Chapman University（查普曼大学）
Autonomous multifunctional image processing via programmable multimode lasing
Tsinghua University（清华大学）；Key Laboratory of Photonic Control Technology, Ministry of Education, Tsinghua University（教育部光子控制技术重点实验室，清华大学）；State Key Laboratory of Precision Space-time Information Sensing Technology（精密时空信息传感技术国家重点实验室）；The University of Hong Kong（香港大学）；City University of Hong Kong（香港城市大学）
Programmable electro-optic frequency comb empowers integrated parallel convolution processing
State Key Laboratory of Optoelectronic Materials and Technologies, School of Electronics and Information Technology, Sun Yat-sen University（中山大学电子与信息工程学院光电材料与技术国家重点实验室）；State Key Laboratory of Precision Measurement Technology and Instruments, Department of Precision Instrument, Tsinghua University（清华大学精密仪器系精密测量技术与仪器国家重点实验室）
Non-volatile programmable silicon photonics using an ultralow loss Sb$_2$Se$_3$ phase change material
可适应、可重构和可编程是下一代硅基光子处理器、神经网络和量子网络的关键功能。相变技术提供了经验证的非易失性电子可编程性，然而迄今为止使用的材料已经显示出与集成光子平台不兼容的过高的光学损耗。在这里，我们证明了以前未开发的材料Sb $_2$ Se $_3$的超低损耗可编程硅光子的能力。在Sb $_2$ Se $_3$中看到的大折射率对比度和超低损耗的有利组合促进了马赫-曾德尔干涉仪中超过10 $π$弧度的前所未有的光学相位控制。为了证明对光的流动的完全控制，我们引入纳米光子数字图案化作为一种概念上的新方法，其足迹数量级小于最先进的干涉仪网格。我们的方法使大量的可能性，在高密度的硅芯片上的光学功能的重新配置。
