提出了一种利用全光纤非平衡Mach-Zehnder干涉仪作为边缘滤波器进行光纤布拉格光栅(FBG)波长移位检测的方案。这种边沿滤波器具有梳状的滤波特性,且其两输出臂滤波特性互补。利用其一对滤波边沿,可以将被测光栅的波长信息转化为功率信息进行检测。在制作时,通过适当改变干涉臂长差可方便地调整测量范围和检测分辨率,具有较大的灵活性。以两种不同的比较运算的方法消除系统功率起伏对测量结果的影响,都得到了较好的结果。采用该检测方案进行了光纤布拉格光栅温度传感实验,得到了±10 pm的波长测量精度。

A method of fiber Bragg grating (FBG) wavelength detection based on an all fiber Mach-Zehnder edge filter is proposed. Each output port of the edge filter shows comb-like transmission characteristics, and its spectrum is opposite to the other port. Wavelength message of FBG sensors is transformed into power message by a pair of the filtering edges of the filter. The wavelength measurement range and resolution are tunable in fabrication by adjusting the length difference of the two interference arms of the filter. And the affection of power variation of the system can be eliminated through two types of comparing calculation. FBG temperature sensing with this wavelength detection method gives a wavelength accuracy of about ±10 pm.