Zhang Fenglei, Liu Kui, Li Zongyang, Cheng Feihu, Feng Xiaohua, Li Ke, Lu Zehuang, Zhang Jie
MOE Key Laboratory of Fundamental Physical Quantities Measurements & Hubei Key Laboratory of Gravitation and Quantum Physics, PGMF and School of Physics, Huazhong University of Science and Technology, 430074 Wuhan, China.
Rev Sci Instrum. 2020 Jan 1;91(1):013001. doi: 10.1063/1.5134928.
We report on the development of a digitally controlled long-term frequency stabilized ultrastable laser source, which serves as an injection laser to stabilize the perimeter of a 3 m × 3 m heterolithic passive resonant gyroscope. We operate the gyroscope at two different cavity modes to reduce back-scattering coupling disturbance for gyroscope locking. This scheme increases the requirement for the injection laser frequency stability since we are using the wavelength of the laser as the length standard for the heterolithic gyroscope structure. The laser source is digitally locked to an ultrastable high-finesse Fabry-Perot cavity and a femtosecond optical frequency comb referenced to an active hydrogen maser simultaneously. The fractional frequency stability of the locked laser is better than 1.2 × 10 for averaging times from 0.1 s to 10 000 s. The short-term frequency stability is limited by the stability of the Fabry-Perot cavity, and the long-term frequency stability is limited by the stability of the frequency comb. The digital locking system enables the laser to run autonomously for weeks and can quickly relock itself within seconds to ensure continuous running of the gyroscope. The digital frequency stabilization technique can also fulfill the requirements of space gravitational waves detection and the next generation space gravity recovery mission.
我们报告了一种数字控制的长期频率稳定超稳激光源的研制情况，该激光源用作注入激光器，以稳定一个3米×3米异质结被动谐振陀螺仪的周长。我们在两种不同的腔模下操作陀螺仪，以减少陀螺仪锁定时的背向散射耦合干扰。由于我们将激光波长用作异质结陀螺仪结构的长度标准，此方案增加了对注入激光频率稳定性的要求。该激光源被数字锁定到一个超稳高精细度法布里-珀罗腔和一个同时参考有源氢脉泽的飞秒光频梳。对于从0.1秒到10000秒的平均时间，锁定激光的分数频率稳定性优于1.2×10⁻⁹。短期频率稳定性受法布里-珀罗腔稳定性限制，长期频率稳定性受光频梳稳定性限制。数字锁定系统使激光器能够自主运行数周，并能在数秒内快速重新锁定自身，以确保陀螺仪持续运行。数字频率稳定技术还能满足空间引力波探测和下一代空间重力恢复任务的要求。
