中国光学（中英文）2025，Vol.18Issue(3)：557-567,11.DOI:10.37188/CO.2024-0080
基于FPGA的PDH激光稳频数字化实现
Digital implementation of PDH laser frequency stabilization system based on FPGA
摘要
Abstract
The traditional Pound-Drever-Hall(PDH)technique utilizes analog devices to actively stabilize the frequency of lasers.However,this results in a bulky system and a rigid control process,making it difficult to meet the requirements of miniaturization and automation of the frequency stabilization system for new ap-plications such as space gravitational wave detection.In this paper,an automatic peak-finding algorithm based on backward difference is specifically designed for frequency discrimination signal peak search,which effectively reduces human intervention in the frequency stabilization process.This method identifies the main signal peak and controls state switching by comparing the time width of consecutive signal peaks.Moreover,it avoids the inherent drawbacks of the conventional thresholding method.We have also designed and built a digital frequency stabilization system based on a field-programmable gate array(FPGA).This system digit-izes and integrates the discrete components of the stabilization servo feedback control into a single FPGA,forming a fast servo feedback loop with a piezoelectric actuator.The digital frequency stabilization system first obtains the frequency discrimination signal locally through an amplitude demodulation,and then achieves automatic peak-finding through the designed backward difference algorithm.Finally,the servo con-troller is activated at the lock-in point,and an incremental digital PID algorithm is used to successfully lock the frequency of a commercial Nd∶YAG laser to a resonance of a 10 cm Fabry-Pérot cavity with a finesse of 350000.During functional testing,the system maintained frequency lock for half an hour,with a wavelength meter measurement showing a relative frequency drift of less than 2 MHz.This result validates the effective-ness of the designed automatic peak-finding algorithm and underscores the merits of FPGA as an effective approach for achieving comprehensive digital laser frequency stabilization control.关键词
激光稳频/Pound-Drever-Hall技术/自动寻峰/FPGAKey words
laser frequency stabilization/Pound-Drever-Hall technique/automatic peak detection/FPGA分类
信息技术与安全科学引用本文复制引用
于龙昆,曹开明,周非凡,范习谦,刘河山,高雪荣,李磐,罗子人..基于FPGA的PDH激光稳频数字化实现[J].中国光学（中英文）,2025,18(3):557-567,11.基金项目
国家重点研发计划(No.2021YFC2201803) （No.2021YFC2201803）
国家自然科学基金(No.42165007)Supported by National Key Research and Development Program(No.2021YFC2201803) （No.42165007）
National Natural Science Foundation of China(No.42165007) （No.42165007）
