本文设计了一种基于声光移频器(AOFS)的光学锁相环系统,实现了DFB半导体激光器与窄线宽光纤激光器的频率锁定。系统采用高速数据采集卡获取主从激光器的相位与频率误差信号,并结合PID控制策略调节本振激光器。同时引入AOFS作为快速精密调谐元件,提升了系统的环路带宽和相位噪声抑制能力。本文首先从理论上分析了系统的工作原理,建立了包含噪声因素的仿真模型,并对锁相性能进行模拟验证。实验结果进一步证实了系统的有效性,显示出良好的频率稳定性和抗干扰能力。 In this paper, an optical phase-locked loop (PLL) system based on acousto-optic frequency shifter (AOFS) is designed to realize the frequency locking of DFB semiconductor laser and narrow linewidth fiber laser. The system uses a high-speed data acquisition card to obtain the phase and frequency error signals of the master-slave laser, and adjusts the local oscillator laser with PID control strategy. At the same time, AOFS is introduced as a fast precision tuning element to improve the loop bandwidth and phase noise suppression ability of the system. In this paper, the working principle of the system is analyzed theoretically, the simulation model including noise factor is established, and the phase-locked performance is simulated and verified. The experimental results further confirm the effectiveness of the system, showing good frequency stability and anti-interference ability.
颗粒物浓度的实时、准确测量一直是国内外研究的热点,尤其在环境监测、工业排放和车间生产中,抗干扰和低浓度颗粒物的有效检测技术越来越受到关注。本文提出了一种基于光散射法强度调制的颗粒物检测方法,以解决外界环境光干扰问题。通过理论分析,探讨了颗粒物粒径、光源波长和散射角度对散射光强度与分布的影响。在光散射法的基础上,采用650 nm激光作为光源,构建了光强度调制颗粒浓度检测系统。系统通过压控恒流源对激光进行12 Hz的强度调制,并通过锁相放大器锁定同频信号并滤除散射信号。对粒径为1 μm的单分散SiO2粉末进行了浓度为25~17,500 mg/m3范围内的散射实验。实验结果表明,与传统检测方法相比,该系统显著降低了外界环境光对检测结果的干扰。Real-time and accurate measurement of particulate matter concentration has been a hot research topic both domestically and internationally, especially in environmental monitoring, industrial emissions, and workshop production. Effective detection of low-concentration particles and anti-interference technology have garnered increasing attention. This paper proposes a particulate matter detection method based on light scattering intensity modulation to address the issue of external light interference. The theoretical analysis explores the effects of particle size, light source wavelength, and scattering angle on the intensity and distribution of scattered light. Based on the light scattering method, a particulate concentration detection system is constructed using a 650 nm laser as the light source. The system modulates the laser intensity at a frequency of 12 Hz using a voltage-controlled constant current source, and a phase-locked amplifier is used to lock the same-frequency signal and filter out scattering signals. Scattering experiments were conducted with monodisperse SiO2 powder of 1 μm particle size in a concentration range of 25~17,500 mg/m3.
