Abstract A known criticality of optical cavities such as Fabry–Perot resonant cavities is the presence of non-linear effects in the build-up of the laser fields inside the cavity itself, which can spoil the characteristics of the error signal used to control the cavity length, usually obtained with the Pound–Drever–Hall phase modulation–demodulation technique. The non-linear effects are primarily caused by high cavity speeds prior to acquiring longitudinal control of the cavity (or “lock”), and they are due to the frequency fluctuations of the laser and to the residual seismic motion affecting the system; such effects are amplified with the increasing of the Finesse of the cavity. In order to overcome this limitation, the cavity speed is effectively slowed down before engaging the lock using a non-linear technique, known as “Guided Lock”; here an optimized version of the algorithm will be presented, which relies on a better estimation of the cavity speed based only on optical signals. The application of this technique to the high-Finesse Fabry–Perot arm cavities of the Advanced Virgo gravitational wave detector will be described. The novel algorithm was applied for the lock acquisition of the Advanced Virgo detector during the O2 Observing Run, in August 2017; the improved algorithm, by dynamically measuring the cavity speed, allowed to implement a predictive capability in slowing down the mirrors, thus improving the efficiency of the lock acquisition procedure for the arm cavities.

中文翻译：

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用于高精细光学腔的引导锁定技术的新算法

摘要 诸如法布里-珀罗谐振腔之类的光腔的已知临界性是在腔内激光场的建立中存在非线性效应，这会破坏用于控制腔的误差信号的特性。长度，通常使用 Pound-Drever-Hall 相位调制-解调技术获得。非线性效应主要是由在获得腔的纵向控制（或“锁定”）之前的高腔速度引起的，它们是由于激光器的频率波动和影响系统的残余地震运动；这种效果随着腔体精细度的增加而放大。为了克服这一限制，在使用非线性技术（称为“导向锁”）接合锁定之前，有效地减慢了腔速度；这里将介绍算法的优化版本，它依赖于仅基于光信号更好地估计腔体速度。将描述该技术在高级 Virgo 引力波探测器的高精细法布里-珀罗臂腔中的应用。2017 年 8 月，在 O2 Observing Run 期间，将新算法应用于 Advanced Virgo 探测器的锁定获取；改进的算法，通过动态测量腔速度，允许在减慢镜子时实现预测能力，从而提高臂腔锁定获取程序的效率。将描述该技术在高级 Virgo 引力波探测器的高精细法布里-珀罗臂腔中的应用。2017 年 8 月，在 O2 Observing Run 期间，将新算法应用于 Advanced Virgo 探测器的锁定获取；改进的算法，通过动态测量腔速度，允许在减慢镜子时实现预测能力，从而提高臂腔锁定获取程序的效率。将描述该技术在高级 Virgo 引力波探测器的高精细法布里-珀罗臂腔中的应用。2017 年 8 月，在 O2 Observing Run 期间，将新算法应用于 Advanced Virgo 探测器的锁定获取；改进的算法，通过动态测量腔速度，允许在减慢镜子时实现预测能力，从而提高臂腔锁定获取程序的效率。