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.