摘要
在远距离相干测量系统中,分布反馈式半导体激光器(DFB-LD)以其直接高速调制特性、低成本、可批量生产等优势成为精密遥测系统的核心光源,因此对DFB-LD的窄线宽和短时频率稳定性提出了更高的要求。为了实现DFB-LD的频率稳定,通过边频锁定与光电反馈回路的方法将激光频率锁定在H^(13)C^(14)N气体吸收谱线1548.956 nm的一侧。将光电探测模块、后续误差信号生成与处理模块和激光器驱动模块集成在一块模拟电路板上,从而有效地降低了系统的噪声;使用除法器代替减法器来产生鉴频信号,大大提高了系统灵敏度和稳频精度;通过这两项技术的改进,将DFB-LD的秒级频率稳定度提高了两个数量级,从稳频前的秒级频率稳定度3.67×10^(-8)提高到稳频后的秒级频率稳定度2.34×10^(-10)。实验结果表明,该DFB-LD稳频方案具有高的稳频精度,且系统结构简单、体积小、可批量生产,适合于无人机机载应用场景,是远距离相干测量系统的理想光源。
A distributed feedback laser diode(DFB-LD) has become the key light source,in which a narrow linewidth and short-term frequency stability are highly demanded,in the far-distance coherent measurement systems due to the characteristics of high-speed direct modulation,low cost,and mass production.To improve frequency stability of a DFB-LD,a new method of frequency locking was proposed.The frequency of the DFBLD was locked to an absorption line of H^(13)C^(14)N gas at the wavelength of 1 548.956 nm by a photoelectric feedback loop based on the principle of side frequency locking.The photodetection module,subsequent error signal generation and processing module and the laser drive module were integrated on the same analog circuit board to minimize the noise of the system.The frequency discrimination signal was generated by using a divider instead of a subtractor to increase the system sensibility and precision of frequency stability significantly.The second-level frequency stability of the DFB-LD was improved by more than two orders of magnitude from3.67×10^(-8) to 2.34×10^(-10) by using two techniques.The experimental results show that the frequency stability scheme of DFB-LD has high precision frequency stability,in addition to the features of simple structure,low cost,mass production and suitable for UAV applications.The DFB-LD is an ideal light source for far-distance coherent measurement.
作者
张明富
杨天新
葛春风
Zhang Mingfu;Yang Tianxin;Ge Chunfeng(Key Laboratory of the Ministry of Education on Optoelectronic Information Technology,School of Precision Instrument and Optoelectronics Engineering,Tianjin University,Tianjin 300072,China)
出处
《红外与激光工程》
EI
CSCD
北大核心
2022年第7期131-137,共7页
Infrared and Laser Engineering
基金
国家自然科学基金面上项目(62075164)
天津市自然科学基金重点项目(19JCZDJC32500)。
关键词
稳频技术
DFB激光器
模拟电路
光电反馈
frequency stabilization technology
DFB laser
analog circuit
photoelectric feedback
