Wavelength multiplexing of four-wave mixing based fiber temperature sensor with oil-filled photonic crystal fiber.

A fiber temperature sensor based on four-wave mixing (FWM) with an oil-filled photonic crystal fiber (PCF) is proposed in this study, and a multipoint measurement based on the wavelength multiplexing of such sensors is constructed for the first time. The sensing performance and signal spectral characteristics of the temperature sensor are theoretically and experimentally studied. The maximum temperature sensitivity of the signal light of 0.207 nm/°C is achieved using a FWM sensing fiber with a length of 10 cm. The signal wavelength response to excitation power is also explored in this experiment. Results showed that the temperature sensor is relatively insensitive to the fluctuation of power change. The wavelength multiplexing of a FWM-based PCF temperature sensor also presents the possibility of multiplexing measurement and multipoint sensing, and high multiplexed capability is theoretically predicted to be obtainable with optimized sensitivity and splicing loss.