# Guided Lock of a Suspended Optical Cavity Enhanced by a Higher Order Extrapolation

## TL;DR

This paper introduces an enhanced guided lock method for suspended optical cavities that incorporates acceleration in the extrapolation process, significantly improving lock acquisition success rates amidst seismic disturbances.

## Contribution

An improved guided lock scheme that includes higher order extrapolation with acceleration, reducing stochasticity in lock acquisition of suspended optical cavities.

## Key findings

- Success rate of lock acquisition increased by a factor of 30.
- The method is less susceptible to seismic disturbances.
- Implemented in a 300-m suspended Fabry-Perot cavity.

## Abstract

Lock acquisition of a suspended optical cavity can be a highly stochastic process and is therefore nontrivial. Guided lock is a method to make lock acquisition less stochastic by decelerating the motion of the cavity length based on an extrapolation of the motion from an instantaneous velocity measurement. We propose an improved scheme which is less susceptible to seismic disturbances by incorporating the acceleration as a higher order correction in the extrapolation. We implemented the new scheme in a 300-m suspended Fabry-Perot cavity and improved the success rate of lock acquisition by a factor of 30.