基于高带宽直接数字频率合成的激光功率稳定技术  

Laser Intensity Stabilization Based on High-Bandwidth Direct Digital Synthesis Technology

作　　者：林堉泓 冀文超 朱明毅 王博葳 张洋 冯佩军 刘相培 戴汉宁 江晓 Lin Yuhong;Ji Wenchao;Zhu Mingyi;Wang Bowei;Zhang Yang;Feng Peijun;Liu Xiangpei;Dai Hanning;Jiang Xiao(School of Physical Sciences,University of Science and Technology of China,Hefei 230026,Anhui,China;Hefei National Research Center for Physical Sciences at the Microscale,University of Science and Technology of China,Hefei 230026,Anhui,China;CAS Center for Excellence in Quantum Information and Quantum Physics,University of Science and Technology of China,Hefei 230026,Anhui,China;Hefei National Laboratory,University of Science and Technology of China,Hefei 230088,China)

机构地区：[1]中国科学技术大学物理学院,安徽合肥230026 [2]中国科学技术大学合肥微尺度物质科学国家研究中心,安徽合肥230026 [3]中国科学技术大学中国科学院量子信息与量子科技创新研究院,安徽合肥230026 [4]中国科学技术大学合肥国家实验室,安徽合肥230088

出　　处：《中国激光》2025年第2期63-71,共9页Chinese Journal of Lasers

基　　金：国家自然科学基金(12074367);中国科学院战略性先导科技专项(XDB35010204);国家重点研发计划(2020YFA0309804);上海市市级科技重大专项(2019SHZDZX01);科技创新2030—“量子通信与量子计算机”重大项目(2021ZD0300106);中央高校基本科研业务费专项。

摘　　要：为满足锶原子光晶格原子钟多路激光的功率稳定需求,提出了一种高集成度的数字功率稳定方法,其特征是:通过在现场可编程逻辑门阵列(FPGA)中实现的比例-积分(PI)控制器直接调整高带宽直接数字频率合成器(DDS)输出信号的幅度,实现声光调制器(AOM)的一级衍射光功率反馈。环内测试结果表明:该方法能将1 Hz处的相对强度噪声(RIN)功率谱密度从-60.1 dBc/Hz降低至-111.2 dBc/Hz,1 Hz处的噪声抑制能力达到51.1 dB,噪声抑制带宽可达10 kHz;160 min内激光功率相对波动从约7.1%降至0.0076%;环路反馈稳定时间为3μs。相比其他方法,该方法具有响应时间快和集成度高的特点,没有压控衰减器带来的附加幅度噪声等的影响,对于星载型或移动型锶原子光晶格钟等紧凑型实验应用具有重要意义。Objective Lasers plays a crucial role in various scientific experiments in fields such as quantum communication,high-resolution atomic spectroscopy,cold-atom physics,and optical clocks.The stability of laser power significantly influences experimental results.For instance,in strontium atomic optical lattice clocks,stabilizing the power of more than a dozen laser beams is required to achieve a clock frequency with fractional stability on the order of 10-18.High-frequency fluctuations in laser power can reduce the signal-to-noise ratio,thereby compromising the stability of frequency standards,whereas low-frequency fluctuations can impact the long-term stability of atomic clocks.Consequently,reliable laser power stabilization technology is indispensable.Furthermore,the portable or space-based applications of cutting-edge experimental devices,such as optical clocks,increase the demand for higher integration,flexibility,and response speed in laser power stabilization.In this study,we leverage the high-speed and low-amplitude noise characteristics of a previously developed high-bandwidth direct digital synthesizer(DDS)circuit and construct a proportional-integral controller in a field-programmable gate array(FPGA)to directly modify the output amplitude of the DDS for laser power feedback control.This approach eliminates the need for an external voltage-controlled attenuator,thereby improving integration and minimizing high-frequency noise interference.Methods Mainstream methods for laser power stabilization can be classified into two types:internal loop control and external loop control.This study selected the latter,using an acousto-optic modulator(AOM)that enables flexible control of output power without affecting the laser output frequency.A portion of the laser beam was split and directed onto a photodiode for power detection.The photodiode output was digitized using a 16-bit analog-to-digital converter(ADC)and compared to a target value to generate an error signal,which was then processed using an incremental digi

关 键 词：直接数字频率合成 激光功率稳定 现场可编程逻辑门阵列 幅度噪声 

分 类 号：TP29[自动化与计算机技术—检测技术与自动化装置]