提出了一种基于相位调制器(PM)和可调谐光滤波器产生线性调频激光信号的方法。该方法利用带有基频的微波线性调频信号作为相位调制器的驱动信号, 窄线宽的激光种子源经相位调制器调制后产生一系列的宽带线性调频激光信号。通过可调谐光滤波器抑制其他边带保留所需阶次的线性调频激光信号。实验结果表明: 当光滤波器保留正二阶调频激光信号时, 获得了调频带宽为2 GHz、调频速率为6 THz/s的线性调频激光信号。在观测时间为1 ms时, 测得的线性调频激光信号的瞬时线宽为3.2 kHz。该方法结构简单, 易于实现, 并且对调频连续波激光雷达、相干光谱分析等测量应用有重要意义。

An approach to generate linear frequency modulation laser source based on an optical phase modulator and a tunable optical filter was proposed. A narrow linewidth fiber laser seed source was modulated by an optical phase modulator, whose driven ratio frequency (RF) signal was generated by the microwave linear frequency modulation signal with a fundamental frequency, and thus a series of wideband linear frequency modulation laser signals were generated. A tunable optical filter was used to select the desired linear frequency modulation optical sideband and suppress the others modulation sidebands. The experimental results show that when the optical filter retains the positive second order modulation sideband, a linear frequency modulation laser signal with a tuning range of 2 GHz and tuning rate of 6 THz/s is obtained. The instantaneous linewidth of the linear frequency modulation laser signal is 3.2 kHz in 1 ms observation time. The system is simple in structure and easy to implement. This technique has important significance for the applications such as frequency modulated continuous wave laser radar and coherent spectroscopy.