【摘要】 本文描述了基于周期极化铌酸锂脊型波导（Periodically-Poled Lithium Niobate/Ridge Waveguide,PPLN/RW）通过参量下转换过程产生全光纤压缩态光源的实验。首先，从理论上研究了参量下转换产生压缩态光场过程中获得高压缩度压缩态光场的影响因素。通过建立理论模型重点研究了波导中有效模式面积对压缩度的影响。当有效模式面积S_eff取极小值134.76μm²，此时波导的归一化倍频效率为85.94%（W·cm²）^-1，无损耗条件下可产生的压缩度为10.5 dB，考虑实验系统总损耗，理论预测压缩度为2.2 dB。实验上利用1 560 nm窄线宽单频激光器注入频器获得780 nm激光光源。780 nm激光作为基于PPLN/RW的参量下转换过程的泵浦光，制备了1 560 nm压缩态光场，实现了全光纤1 560 nm压缩态光源。在分析频率1.5 MHz处，实验测得压缩态光场的最大压缩度为2.04 dB，压缩态光源带宽为80 MHz。本研究可为实现基于波导的小型化全光纤压缩光源提供理论依据和实验参考，可为量子信息处理、量子计算和量子传感提供更优质的量子光源。更多还原

【Abstract】 Objective. In recent years, squeezed light has demonstrated significant potential in precision measurement, quantum communication, and quantum computing. To further broaden its applications, the miniaturization and compact integration of squeezed light sources have become key research directions.Methods. We investigate the generation of a 1 560 nm squeezed light field via a single-pass parametric down conversion process in a fiber-coupled periodically poled lithium niobate ridge waveguide（PPLN/RW）. First, we theoretically analyzed the correlation between second-harmonic generation（SHG） and the parametric down conversion process in the PPLN ridge waveguide（PPLN/RW） and systematically investigated the factors influencing the generation of highly squeezed light fields during the parametric down conversion process. By establishing a theoretical model, we focused on exploring the effect of the mode field radius ratio coefficient k between the second harmonic and fundamental light and the effective mode area S_eff on the squeezing degree. In the experimental section, we investigated the dependence of the second-harmonic generation efficiency on the coupled fundamental power by measuring the SHG efficiency of the waveguide. Subsequently, by scanning the relative phase between the local oscillator and the squeezed light, we measure both the squeezing and anti-squeezing of the squeezed light field generated via the waveguide-based parametric down conversion process.Results and Discussions. Theoretical results show that when the mode field radius ratio coefficient reaches k = 0.72, the effective mode area S_eff reaches a minimum value of 134.76 μm², corresponding to a normalized second-harmonic generation efficiency of ξ = 85.94%（W·cm²）^-1. Then, we realized the second-harmonic generation of the waveguide. The SHG efficiency on the coupled fundamental power was measured. Subsequently, by scanning the relative phase between the local oscillator and the squeezed light, the squeezing and anti-squeezing of the squeezed light field generated via the waveguide-based parametric down conversion process were measured. With a coupled pump power of 430 mW, we achieved a squeezing level of 2.04 dB and an anti-squeezing level of 5.53 dB at an analysis frequency of 1.5 MHz. Furthermore, by varying the pump power, we explore the dependence of squeezing and anti-squeezing on the pump power, revealing good agreement between the experimental data and the theoretical fit. Additionally, we measured the squeezing bandwidth over a frequency range of 1～80 MHz, providing valuable reference data for optimizing the performance of squeezed light sources. If the transmission loss is significantly reduced and the coupling efficiency is improved through process enhancements, the squeezed degree of the PPLN/RW-based all-fiber squeezed source can be greatly increased.Conclusions. This study provides theoretical and experimental references for realizing miniaturized all-fiber squeezed light sources based on waveguides, offering high-quality quantum light sources for quantum information processing, quantum computing, and quantum sensing.更多还原