Chloroform-infiltrated photonic crystal fiber with high-temperature sensitivity.

The temperature sensor is the core part of the temperature measurement instrument, and its performance directly determines the temperature measurement accuracy. Photonic crystal fiber (PCF) is a new type of temperature sensor with extremely high potential. In this paper, we propose a high-performance, structurally simple, liquid-filled PCF temperature sensor, which is based on a SMF-PCF-SMF (single mode fiber, SMF) sandwich structure. By adjusting the structural parameters of the the PCF, it is possible to obtain optical properties that are superior to those of ordinary optical fibers. This allows for more obvious responsive changes of the fiber transmission mode under small external temperature changes. By optimizing the basic structure parameters, a new PCF structure with a central air hole is designed, and its temperature sensitivity is -0.04696 nm/°C. When filling the air holes of PCFs with temperature-sensitive liquid materials, the response of the optical field against the temperature fluctuations can be effectively enhanced. The Chloroform solution is used to selectively infiltrate the resulting PCF owing to its large thermo-optical coefficient. After comparing various filling schemes, the calculation results show that the highest temperature sensitivity of -15.8 nm/°C is finally realized. The designed PCF sensor has a simple structure, high-temperature sensitivity, and good linearity showing great application potential.