为了研究基于压电陶瓷的法布里-珀罗(F-P)波长滤波器扫描非线性的物理机理及优化方案, 搭建了基于F-P滤波器的扫频激光器。用基于梳状滤波器的透射时域法研究了扫频激光器输出的非线性特性, 获得了不同扫描频率下的扫频非线性特性的变化情况, 认为这是由于可调谐滤波器中的执行器——压电陶瓷的容性负载特性引起的。结合光谱测量法, 获得了动态扫频线性度、扫频范围与驱动频率的关系, 实验结果与理论分析结果相符。最后, 提出了优化扫频非线性的驱动参数方案。通过在驱动源后增加电压跟随器提高了驱动源的负载能力和高速扫频的线性响应特性, 并应用于光纤光栅解调。实验得到了1 000 Hz扫频速度下的线性解调结果, 即解调线性度为0.998 44。

To explore the physical mechanism of sweeping nonlinearity of a Fabry-Perot(F-P) tunable filter based on a PZT and to obtain the optimized scheme for the characteristics of linear wavelength sweeping, a wavelength-swept laser based on the F-P tunable filter was developed. The transmission time domain method was used to research the output nonlinearity of the wavelength-swept laser and the changed sweeping nonlinear characteristics in different sweeping frequencies were obtained. Then, it points out the change is caused by capacitive load characteristics of the PZT from the actuator in the tunable filter. With spectroscopy, the relationship among dynamical sweeping nonlinearity, sweeping range and driving frequency was obtained and it is in good agreement with that of the theoretical analysis. Finally, a new drive scheme based on a voltage follower was proposed to optimize the characteristics of linear wavelength sweeping. The experimental results show that this method promotes the linear responsibility of high-speed wavelength-sweeping. The scheme is applied in FBG interrogation system and obtained demodulation nonlinearity is 0 998 44 at a wavelength-swept speed of 1 000 Hz.