The entanglement distribution network connects remote users by sharing entanglement resources, which is essential for realizing quantum internet. We propose a photonic-reconfigurable entanglement distribution network (PR-EDN) based on a silicon quantum photonic chip. The entanglement resources are generated by a quantum light source array based on spontaneous four-wave mixing in silicon waveguides and distributed to different users through time-reversed Hong–Ou–Mandel interference by on-chip Mach–Zehnder interferometers with thermo-optic phase shifters (TOPSs). A chip sample is designed and fabricated, supporting a PR-EDN with 3 subnets and 24 users. The network topology of the PR-EDN could be reconfigured in three network states by controlling the quantum interference through the TOPSs, which is demonstrated experimentally. Furthermore, a reconfigurable entanglement-based quantum key distribution network is realized as an application of the PR-EDN. The reconfigurable network topology makes the PR-EDN suitable for future quantum networks requiring complicated network control and management. Moreover, it is also shown that silicon quantum photonic chips have great potential for large-scale PR-EDN, thanks to their capacities for generating and manipulating plenty of entanglement resources.

Faint light spectroscopy has many important applications such as fluorescence spectroscopy, lidar, and astronomical observations. However, the long measurement time limits its application to real-time measurement. In this work, a photon counting reconstructive spectrometer combining metasurfaces and superconducting nanowire single-photon detectors is proposed. A prototype device was fabricated on a silicon-on-insulator substrate, and its performance was characterized. Experiment results show that this device supports spectral reconstruction of mono-color lights with a resolution of 2 nm in the wavelength region of 1500–1600 nm. Its detection efficiency is 1.4%–3.2% in this wavelength region. The measurement time required by the photon counting reconstructive spectrometer was also investigated experimentally, showing its potential to be applied in scenarios requiring real-time measurement.

Tunable coupled mechanical resonators with nonequilibrium dynamic phenomena have attracted considerable attention in quantum simulations, quantum computations, and non-Hermitian systems. In this study, we propose tunable mechanical-mode coupling based on nanobeam-double optomechanical cavities. The excited optical mode interacts with both symmetric and antisymmetric mechanical supermodes and mediates coupling at a frequency of approximately 4.96 GHz. The mechanical-mode coupling is tuned through both optical spring and gain effects, and the reduced coupled frequency difference in non-Hermitian parameter space is observed. These results benefit research on the microscopic mechanical parity–time symmetry for topology and on-chip high-sensitivity sensors.

硫化物玻璃是发展非线性集成光学器件的良好材料，特殊的理化特性使得硫化物玻璃集成光学波导的制备成为研究的难点。对硫化物玻璃波导的制备工艺进行了综述，重点介绍利用硫化物玻璃在熔融状态下流动性好的特点，采用热熔融自回流方法制备硫化物玻璃波导的工艺。该方法避免了对硫化物玻璃薄膜完整性的破坏，以及光刻胶显影液对硫化物玻璃材料的腐蚀作用，可以得到高质量的具有小模场面积的倒脊型硫化物玻璃波导。实验测试表明，采用热熔融自回流方法制备的硫化物玻璃波导具有良好的三阶非线性光学特性和受激布里渊散射特性。最后，展望了采用该方法发展硫化物玻璃非线性集成光学器件及其片上系统的研究方向和前景。

The orbital angular momentum (OAM) carried by photons defines an infinitely dimensional discrete Hilbert space. With OAM modes, high-dimensional quantum states can be achieved for quantum communication and cryptography. Here we demonstrate a heralded single-photon source with a switchable OAM mode, which consists of a heralded single-photon source and an integrated OAM emitter as the mode converter. As the first step, the heralded single-photon source is based on the dispersion-shifted fiber. In this work, the OAM mode (quantized by topological charge l) carried by the heralded single photon (at fixed wavelength of 1555.75 nm) can be switched within the range of l=3–7 while the mode purity is more than 80%.