分布式光纤Bragg光栅波长校准方法

Wavelength calibration method for distributed fiber Bragg grating

提出了一种利用标准参考光谱进行波长校准的方法。实验中利用由宽带光源和光纤可调谐滤波器组成的可调谐光源分别扫描了参考光谱和传感光栅的光谱。在参考通道,ITU标准参考模块的输出是具有固定波长的梳状光谱。利用高斯拟合算法计算出由标准参考透射谱峰值输出的对应的驱动电压,通过样条插值函数获得了滤波器输出波长与驱动电压的关系。计算光栅反射谱峰值对应的驱动电压,利用上面获得的滤波器输出波长与驱动电压的关系式可以计算出传感光栅的Bragg波长。实验结果表明,在较大的波长范围内实现了对多个传感光栅的波长校准,减小了由滤波器非线性输出造成的测量误差,具有较高的重复性。

A wavelength calibration method for distributed fiber Bragg grating （FBG） employing standard reference is proposed. In experiment broad band light source combined with a fiber tunable filer scans reference spectrum and sensing spectrum respectively. In standard reference channel, ITU standard reference creates a comb spectrum with fixed wavelength. The driving voltage corresponding to peak wavelength of reference speetrum can be calculated by Gaussian-fitting algorithm. The liner relationship between wavelength and vohage can be achieved. In sensing channel, the peak position of reflected spectrum can be located by employing Gaussian-fitting algorithm, and wavelength reference section can be be obtained. Bragg wavelength of FBG can be calculated by emplying linear interpolation between two adjacent reference wavelength, Experimental result show that the wavelength of mult-FBG can be calibrated in a large wavelength scope, the measurement error caused by nonlinear out put of filter decreases, and wavelength measurement result has good repetition.