Highly sensitive nonlinear temperature sensor based on soliton self-frequency shift technique in a microstructured optical fiber

A novel fiber-optic soliton self-frequency shift (SSFS) temperature sensor fabricated using an in-house made microstructured optical fiber was proposed. Based on this sensor, SSFS-based sensing was systematically investigated with the variation of average pump power and pump wavelength. By detecting the central wavelength shift of the 3-dB bandwidth of the soliton with the change in temperature, the sensing performance of the proposed sensor was evaluated experimentally and theoretically, subject to the average pump power and pump wavelength. At the generation of the fundamental soliton, when the pump wavelength was fixed, the higher the average pump power, the higher the temperature sensitivity. When the average pump power was fixed, the longer the pump wavelength, the higher the temperature sensitivity. The maximum temperature sensitivity of the proposed sensor was 1.759 nm/celcius at an average pump power of 300 mW and pump wavelength of 1600 nm. This temperature sensor exhibited excellent properties, such as high sensitivity, a simple structure, an easy fabrication process, good mechanical strength, and low cost, rendering it highly applicable in fields such as food quality control, environmental monitoring, and biomedical testing.(c) 2021 Elsevier B.V. All rights reserved.