提出了一种低成本的新型强度调制型光纤温度传感器。该传感器主要由宽谱光源、三端口光环形器、光纤耦合器、偏振控制器、PMF光纤、光电探测器,以及信号处理单元组成。在较短的PMF光纤条件下, 温度变化会对PMF光纤双折射产生直接影响, 导致两相干光束产生一定的相移变化, 使经过Sagnac环干涉后具有不同的透射光谱, 即发生波长漂移。利用光电转换和信号处理, 将检测到的光信号转换为电压信号, 对其进行解算从而完成对温度的检测。在无需光谱分析仪的情况下, 通过对Sagnac干涉仪的透射光谱进行信号处理, 根据随温度的变化函数解算出测量温度。在25~50.5℃的温度范围内进行了实验, 测试结果表明该光纤温度传感器的灵敏度为0.066mW/℃, 分辨率为0.34℃。

In order to realize the design of temperature sensor with lower cost, a new type of intensity modulated optical fiber temperature sensor is proposed. It mainly consists of light source with band-width spectrum, 3-port circulator, fiber coupler, polarization controller, polarization maintaining fiber (PMF), photodetector and signal processing unit. Under the condition of short PMF fiber, the temperature change will have a direct impact on the birefringence of PMF fiber, resulting in a certain phase shift change of the two coherent beams, thus they will have different transmission spectra after Sagnac interferometer, that is, wavelength drift occurs. By using photoelectric conversion and signal processing, the detected light signal is converted into a voltage signal, which is solved to complete the temperature detection. Therefore, without the need for a spectrum analyzer, the measured temperature can be calculated according to the temperature-dependent change function by measuring the transmission spectrum of the Sagnac interferometer. Experiments were carried out in the temperature range of 25~50℃. The test results show that the sensitivity of the optical fiber temperature sensor is 0.066mW/℃, and the resolution is 0.34℃. It has good application value for constructing temperature monitoring optical fiber sensor network.