Huang Canhong, Lu Xinghua, Jiang Youen, Wang Xiaochao, Qiao Zhi, Fan Wei
Appl Opt. 2017 Feb 20;56(6):1610-1615. doi: 10.1364/AO.56.001610.
FM-AM modulation of high-power lasers significantly affects laser performance. Therefore, precise measurement of the FM-AM modulation depth is necessary. The subsequent FM-AM modulation generated by group velocity dispersion when the laser pulse propagates through a fiber affects the measurement accuracy. In order to eliminate this effect, a waveform-acquisition module is proposed that converts a broad-spectrum pulse of 1053 nm to a narrow-spectrum pulse of 1550 nm, without affecting the waveform. In addition, a signal-processing algorithm based on the orthogonal matching pursuit method is implemented to remove the sampling noise from the waveform. In this way, the signal-to-noise ratio of the measurement can be readily improved. Both theoretical and experimental results indicate that the proposed FM-AM modulation detection system is effective and economical. It can measure the FM-AM modulation depth precisely, and therefore shows considerable promise for future applications in high-power lasers.
高功率激光器的调频调幅调制会显著影响激光性能。因此，精确测量调频调幅调制深度是必要的。激光脉冲在光纤中传播时，群速度色散产生的后续调频调幅调制会影响测量精度。为了消除这种影响，提出了一种波形采集模块，它将1053nm的宽谱脉冲转换为1550nm的窄谱脉冲，且不影响波形。此外，还实现了一种基于正交匹配追踪法的信号处理算法，以去除波形中的采样噪声。通过这种方式，可以很容易地提高测量的信噪比。理论和实验结果均表明，所提出的调频调幅调制检测系统有效且经济。它能够精确测量调频调幅调制深度，因此在高功率激光器的未来应用中显示出巨大的潜力。
