针对填充液体的光子晶体光纤温度传感器灵敏度较低的问题, 文章提出了一种基于模式耦合的高灵敏光子晶体光纤温度传感器, 光子晶体光纤的纤芯作为传光通道, 填充液态乙醇和氯仿的液芯作为耦合通道, 当纤芯与液芯发生模式耦合时, 纤芯的限制损耗谱会出现一个狭窄的损耗尖峰。损耗峰的位置随温度的变化而漂移。光子晶体光纤的纤芯和液芯相互独立, 可以分别调整其传输特性。利用有限差分算法对传感器的特性进行了仿真研究, 结果表明, 设计的光纤结构具有良好的温度传感特性, 耦合波长随温度升高而红移, 在10~35 ℃范围内, 温度检测灵敏度最高可达44.16 nm/℃, 光纤结构参数的变化对灵敏度影响较小。

Aiming at the problem of low sensitivity of liquid-filled photonic crystal fiber temperature sensor, a high-sensitivity photonic crystal fiber temperature sensor based on mode-coupling principle is proposed. We use the core of photonic crystal fiber as the light transmission channel and the liquid core filled with ethanol and chloroform as the coupling channel. When the mode coupling occurs between the fiber core and liquid core, a narrow high loss peak is formed in the confinement loss spectrum. The position of the loss peak shifts with the change of temperature. Because the core and the liquid core of the photonic crystal fiber are independent of each other, their transmission characteristics can be adjusted respectively. The properties of this sensor are analyzed by the finite difference method. Results show that the designed optical fiber structure has good temperature sensing characteristics, and the coupling wavelength is red-shift with the increase of temperature. The maximum sensitivity of temperature detection is up to 44.16 nm/℃ between 10℃ and 35℃, and the influence of fiber structure parameters on the sensitivity is not obvious.