飞秒压缩光相位抖动抑制  

Phase Jitter Suppression by Femtosecond Squeezed Light

作　　者：孙倩 刘宏波 张云豪 刘奎[1,2] 郜江瑞 Sun Qian;Liu Hongbo;Zhang Yunhao;Liu Kui;Gao Jiangrui(State Key Laboratory of Quantum Optics and Quantum Optics Devices,Institute of Opto-Electronics,Shanxi University,Taiyuan 030006,Shanxi,China;Collaborative Innovation Center of Extreme Optics,Shanxi University,Taiyuan 030006,Shanxi,China)

机构地区：[1]山西大学光电研究所量子光学与光量子器件国家重点实验室,山西太原030006 [2]山西大学极端光学协同创新中心,山西太原030006

出　　处：《中国激光》2024年第22期236-242,共7页Chinese Journal of Lasers

基　　金：中央引导地方科技发展资金(YDZJSX20231A001);国家自然科学基金(12074233)。

摘　　要：长期稳定的压缩光源是实现可靠的量子协议、构建量子网络,特别是进行高精度量子测量的核心量子资源。然而,由于飞秒脉冲相较于连续光对光路抖动更加敏感以及制备装置更为复杂,因此获得长期稳定的飞秒脉冲压缩光源更为困难。基于同步泵浦光学参量振荡器,在无信号场注入的情况下,通过本底光和泵浦光之间的锁相环路有效抑制了压缩测量过程中68.05%的随机相位抖动,实现了飞秒脉冲压缩真空态光场的长期稳定压缩输出测量,长期压缩度由0.6 dB提高至3.2 dB。长期稳定的飞秒脉冲压缩光源有助于构建和实现多模量子网络,特别是长时间时域量子测量。Objective As a crucial quantum light source, the squeezed state of light plays a pivotal role in advancing quantum information,quantum networks, quantum computing, and quantum-precision measurements. The emergence of optical frequency combs is of great significance in the field of precision measurements and offers a novel avenue for achieving high-precision and long-distance measurements. The optical frequency comb represents a new class of light sources characterized by periodic ultrashort pulses,resulting in a spectrum with equally spaced frequencies. Based on the special properties of the optical frequency comb, researchers applied it to the quantum field, obtaining the “quantum frequency comb,” which is a new quantum resource contributing to the development of the quantum field. The generation of a femtosecond squeezed state in an optical field is challenging because of the extended cavity and optical path of the resonator. Compared with continuous waves, femtosecond pulses are more sensitive to external noise, posing difficulties in achieving a stable squeezed state. This limitation hinders the practical application of femtosecond squeezed light in quantum information protocols. Thus, achieving a long-term stable femtosecond pulse-squeezed state of the light field is considered a fundamental requirement.Methods A titanium sapphire laser is used to generate pulsed light with a central wavelength of 850 nm, pulse width of 130 fs, and pulse repetition rate of 76 MHz. A femtosecond pulse-squeezed vacuum state of the light field is obtained without signal injection based on a synchronously pumped optical parametric oscillator below the threshold. Nevertheless, the primary hurdle is the effective suppression of noise through the implementation of phase-locking between the signal and local components. To address this, the relative phase between the pump and local field is locked to suppress the phase noise. A bismuth borate(BIBO) nonlinear crystal with a thickness of 2 mm is used to generate the second harmonic

关 键 词：压缩态 飞秒脉冲 相位抖动 锁相环 

分 类 号：O436[机械工程—光学工程]