Design and optimization of Bragg grating fiber temperature and strain nanosensors using BaO impurities and polymer fibers

In this paper, we design the temperature and strain nanosensors using fiber Bragg gratings. Bragg wavelengths for temperature and strain nanosensors are 1555 and 1549 nm, respectively. The design of strain and temperature nanosensors has been investigated by using barium impurity and its injection into silica fiber core as well as by using methyl methacrylate polymer fiber. Temperature changes in the Bragg grating nanosensors change the modulation depth of the refractive index and consequently change the Bragg wavelength. As a result, by using polymer fiber and impurity injection such as benzophenone into the polymer fiber core, the thermo-optical parameters are increased and as a result the temperature sensitivity of the designed nanosensor is greatly enhanced. The sensitivity obtained for the temperature nanosensor was obtained using polymer fiber -0.3223nm /°C. Also, strain changes in Bragg gratings in addition to changing the depth of refractive index modulation also cause changes in the periodicity of gratings. By injecting barium impurities into the silica fiber core, the strain-optical parameters were increased and due to the strain relationship with the Bragg wavelength variations, the strain sensitivity of the designed nanosensor increased. The sensitivity obtained for the designed strain nanosensor was 0.0019nm/μ. Also, due to the proper selection of grating parameters, the reflectance intensity at the Bragg wavelength of the designed nanosensors is approximately 100, and the transmission intensity at the Bragg wavelength is reduced, thereby reducing the intensity, losses of the designed nanosensors, significantly Acceptance has declined.