一种新的白光光纤传感系统波长解调方法

A Novel Wavelength Demodulating Method for White Light Optical Fiber Sensor System

提出了一种新的白光非本征法布里珀罗干涉(EFPI)光纤传感系统的干涉谱处理方法,在白光法布里珀罗干涉光纤传感系统中,一个中心波长为850 nm的发光二极管(LED)作为宽谱光源,HR2000高分辨力微型光谱仪用来测量返回的干涉光谱。通过跟踪干涉光谱中的特定谱峰点,法布里珀罗干涉传感器的腔长值可以被解调出来。应用反向传播神经网络,解决了单峰测量方式的级次模糊问题。反向传播神经网络能够分辨出干涉谱中不同谱峰的干涉级次,因而可以进行多个谱峰的连续跟踪。从而实现了高精密度、大动态范围的测量。进行了基于这种干涉谱处理方法的白光法布里珀罗干涉传感系统的应变测量实验。利用该传感系统实现了精密度达0.1με,500με范围的应变测量。

A novel data processing method for demodulating the information from the interference spectrum of a white light extrinsic Fabry-Pérot interferometer （EFPI） sensor system is presented. In the white light EFPI sensor system, an 850 nm LED is used as the broadband light source and a HR2000 high resolution miniature spectrometer is used to measure the interference spectrum. Through tracing a special peak point in the interference spectrum, the air gap value of the EFPI sensor can be demodulated. The order ambiguity problem of single peak tracing method is solved through the application of BP neural networks. As the BP neural networks can distinguish the interference orders of the peaks in the interference spectrum, many peaks can be traced continuously. Both high precision and large dynamic range are achieved. The data processing method is demonstrated on a white light EFPI strain sensor system. 0.1με precision and 500με measurement range are achieved with this system.