Title: Wafer-Scale Squeezed-Light Chips Show Chinese title

Title: 晶圆级压缩光芯片

Abstract: Squeezed-light generation in photonic integrated circuits (PICs) is essential for scalable continuous-variable (CV) quantum information processing. By suppressing quantum fluctuations below the shot-noise limit, squeezed states enable quantum-enhanced sensing and serve as a standard resource for CV quantum information processing. While chip-level squeezed-light sources have been demonstrated, extending this capability to the wafer level with reproducible strong squeezing to bolster large-scale quantum-enhanced sensing and information processing has been hindered by squeezed light's extreme susceptibility to device imperfections. Here, we report wafer-scale fabrication, generation, and characterization of two-mode squeezed-vacuum states on a fully complementary metal-oxide-semiconductor (CMOS)-compatible silicon nitride (Si$_3$N$_4$) PIC platform. Across a 4-inch wafer, 8 dies yield 2.9-3.1 dB directly measured quadrature squeezing with $< 0.2$ dB variation, demonstrating excellent uniformity. This performance is enabled by co-integrating ultralow-loss, strongly overcoupled high-$Q$ microresonators, cascaded pump-rejection filters, and low-loss inverse-tapered edge couplers. The measurements agree with a first-principles theoretical model parameterized solely by independently extracted device parameters and experimental settings. The measured squeezing level can be further improved by enhancing the efficiencies of off-chip detection and chip-to-fiber coupling. These results establish a reproducible, wafer-scale route to nonclassical-light generation in integrated photonics and lay the groundwork for scalable CV processors, multiplexed entanglement sources, and quantum-enhanced sensing. Show Chinese abstract

Abstract: 在光子集成电路（PICs）中产生压缩光对于可扩展的连续变量（CV）量子信息处理至关重要。通过抑制低于散粒噪声极限的量子涨落，压缩态能够实现量子增强的传感，并作为CV量子信息处理的标准资源。虽然已经实现了芯片级的压缩光光源，但由于压缩光对器件缺陷极端敏感，将其能力扩展到晶圆级别并实现可重复的强压缩以增强大规模量子增强传感和信息处理受到了阻碍。在此，我们报告了在完全兼容互补金属-氧化物-半导体（CMOS）的氮化硅（Si$_3$N$_4$）PIC平台上，晶圆规模的两模压缩真空态的制造、生成和表征。在整个4英寸晶圆上，8个芯片产生了2.9-3.1 dB直接测量的正交压缩，变化为$< 0.2$ dB，展示了出色的均匀性。这种性能是通过集成超低损耗、强过耦合的高$Q$微谐振器、级联泵抑制滤波器和低损耗逆锥形边缘耦合器实现的。测量结果与仅由独立提取的器件参数和实验设置参数化的第一性原理理论模型一致。通过提高片外检测和芯片到光纤耦合的效率，可以进一步改善测量的压缩水平。这些结果建立了一种可重复的晶圆规模方法，在集成光子学中生成非经典光，并为可扩展的CV处理器、多路复用纠缠源和量子增强传感奠定了基础。