半非平面单块激光器强度噪声及其抑制的研究

实验研究了半非平面单块固体环形Nd∶YAG激光器的强度噪声特性和抑制技术。结果表明,弛豫振荡仍是该种激光器强度噪声最主要的来源。噪声峰值频率随抽运和输出功率的增加向高频方向移动,同时噪声峰宽度增加幅度降低,且在峰值频率附近发生180°相位跃变。采用光电反馈方法设计和制作了包含低噪声宽带接收、比例积分微分(PID)调整等单元组成的噪声抑制电路,测量了整个系统及各部分的传递函数,实现了强度噪声的抑制。当弛豫振荡峰值频率为600kHz时,噪声峰值处和低频区域幅度降低分别接近40dB和15dB。

Study on the Properties and Suppression of the Intensity Noise in Semi-Nonplanar Monolithic Lasers

The intensity noise properties and the suppression technology of the monolithic NdYAG semi-nonplanar ring laser are investigated in this paper. The experiment shows that the relaxation oscillation noise (RON) is the main reason to bring intensity noise in this type of laser. With the pump and output power increasing, the center frequency of the RON peak moves to the high frequency, the width of noise spectrum increases and its peak value decreases. Phase changes by 180 across the resonance at the same time. An optoelectronic feedback circuit including low noise wideband receiver and proportional integral differential (PID) adjustment is designed. The transfer function for the laser and complete loop is measured. Under the condition of the center frequency of the (600 kHz) RON, the experiment results show that the RON peak value and low frequency intensity noise reduced, respectively, about 40 dB and 15 dB.