在光腔衰荡系统中,不同性能的脉冲激光器输出的激光脉宽不同,直接影响着衰荡信号的形状,从而决定了反射率测量结果与真实值的偏离程度。根据光束传输变换规律和信号叠加方式,利用数据拟合方法,建立了激光脉宽对衰荡信号和测量结果的影响模型。通过数值运算,模拟了不同脉宽下衰荡信号的波形变化情况,并分析了当激光脉冲宽度不同时反射率测量结果随腔镜真实值的变化,进而研究了激光脉宽对衰荡法测量结果的影响。研究表明,目前的数据处理方法不能得到准确的反射率测量结果,并给出了测量结果的标校方法。

Different capability laser has different pulse width, which influences the figure of ring-down waveform in the cavity ring-down system (CRDS), and makes measurement result relative departure from true reflectivity.According to propagation equation of Gaussian beam and overlap-add of signal, a theory model is set up by data fitting to research the influence of pulse laser on its ring-down signal and its metrical results. The change of ring-down waveform is numerically simulated in different cases by this model, and it is also calculated how the measurement result varies with the true reflectivity. Based on this, it is analyzed that relation between waveform of the laser and measured reflectivity of the CRDS. Results show that current data processing can not acquire exact measured reflectivity. and a collating ways for measured reflectivity is put forward.