Highly-sensitive optical fiber temperature sensors based on PDMS/silica hybrid fiber structures

It is very important to accurately measure temperature in industrial production and scientific research. In this work, the high-sensitivity temperature sensors are proposed based on the modal interference principle. To increase the sensitivity, polydimethylsiloxane (PDMS) as the temperature sensitive material in filled into the hollow core fiber to fabricate the PDMS/silica hybrid fiber structures. The hybrid fiber structure is inserted between two pieces of single mode fiber as the sensing section. The environmental temperature can modify the phase delays of the modes in the hybrid fiber with different values. According to the principle of modal interference, the resonance wavelength of the transmission spectrum is shifted with temperature variation. The experimental results showed that the sensitivity of the sensor was −384 pm/°C in the range of 25 °C–80 °C when the core diameter of the hollow core fiber was 30 μm. The proposed temperature can be used to monitor the temperature in real time accurately in fields of biological detection, chemical and pharmaceutical industries.