增益开关F-P激光器抖动的计算和测量

Calculation and measurement of jitter in gain-switch F-P laser

为了能够精确测量增益开关激光脉冲的抖动,应用傅里叶变换和自相关函数,理论分析了谐波频谱分析法测量激光脉冲抖动的数学模型、测量原理,修正了DavidA.Leep等人建立的基于功率谱测量脉冲抖动的误差,推导出了普适的测量激光脉冲抖动的数学表达式,并数值模拟了不同情况下激光脉冲功率谱的表现形式;利用谐波频谱分析法测量了外连续光注入下增益开关F-P激光脉冲的抖动,时基抖动为0.905ps、振幅噪声为2.83%,并与取样示波器的测量结果进行比较。结果表明在脉冲抖动较小、且重复频率较低的情况下,利用谐波频谱分析法测量脉冲抖动具有更高的精确度,其精确度可以达到飞秒量级。

In order to measure jitter of gain-switched laser precisely, we analyze theoretically the math model and measurement principle of harmonic spectrum analysis used to measure laser pulse jitter. The error in pulse jitter measurement, which based on power spectrum measurement and was established by David A. Leep etc., is corrected. The universal math formula for measuring pulse jitter was deduced and the power spectrum of pulse in different conditions was numerically simulated. The pulse jitter of gainswitched Fabry-Perot laser with external cw-light injection was experimentally investigated by using harmonic spectrum analysis. The time jitter is 0.905 ps and amplitude noise is 2.83%. Compared with the outcome of sample oscilloscope measurement, it indicates that the harmonic spectrum analysis measurement is more precise and the accuracy is up to the magnitude of fs in the case of small jitter high repeat frequency.