基于波长与强度双解调的光纤温度传感器

Optic fiber temperature sensor based on double-demodulation of the wavelength and intensity

为了更好的了解光纤传感原理,并提高温度光纤传感器的各方面性能,提出一种新型的具有波长与强度双解调的光纤温度传感器。将30mm的保偏光纤(PMF)的两端分别与单模光纤(SMF)进行腰椎放大熔接,形成两个腰椎,构成全光纤马赫泽德尔(M-Z)温度传感器。温度的变化将会引起光纤的纤芯模与包层模相位差的变化,从而导致干涉光谱的变化。以25-70℃作为测试温度,通过光谱仪(OSA)监测宽带光源经传感器后的干涉光谱。实验结果表明,温度升高,特征峰波长在向长波长方向移动,并且其强度在逐渐增大。因此,采用波长与强度双解调的方法对温度进行测量,其灵敏度分别为0.127nm/℃和0.32dB/℃,对应的分辨率分别为0.16℃和0.03℃。这个双解调的全光纤温度传感器制造简单、成本低、体积小和结构稳固,而且具有很高的分辨率,因此适用于实际测量。

In order to better understand the principle of optic fiber sensing, and to improve various aspects of performance of the optical fiber sensor for the temperature, a novel optic fiber temperature sensor based on double-demodulation of the wavelength and intensity is presented. A 30 mm polarization maintaining fiber （PMF） is spliced with lumbar enlarge between two conventional single-mode fibers （SMFs） to construct an all fiber M-Z sensor. The phase difference between the cladding and core regions is changed with the external temperature increases, and then the interference spectrum is changed. The light source is a broadband super luminescent light-emitting diode （SLED） with wavelength range from 1450 nm to 1650 nm. The spectrum is measured by an optical spectrum analyzer （OSA） with a resolution of 20 pm The temperature is from 25 ℃ to 75 ℃. The results show that the wavelength has a red shift and intensity is gradually enlarged with temperature increases. Therefore, the sensor uses the method of the wavelength and intensity for temperature measurement, and the sensitivities of the sensor are 0. 127 nm/℃ and 0. 32 dB/℃,respectively, corresponding to the resolutions of 0. 16℃ and 0.03℃. The sensor has the advantages of simple manufacture, low cost, structural stability and high resolution, so it can be applied to the actual measurement.