Design of longitudinal strain and temperature fiber bragg grating sensor in polarization-maintaining panda fiber

In this paper, a comprehensive model is developed in order to take into account the effect of stress birefringence, longitudinal strain and temperature change on a sensor based on a Fiber Bragg Grating (FBG) written in a Polarization-Maintaining (PM) Panda Fiber. The electromagnetic and mechanical investigation is performed via the Finite Element Method (FEM) to determine stress-induced birefringence and its effect on the light propagation in single mode polarization maintaining optical fibers. The sensing feature of a FBG, subjected to longitudinal strain and temperature variation, is investigated with reference to the resonant wavelength shift. The reflection spectra, obtained by using transfer matrix method, show high sensitivity optical responses to thermal and mechanical stresses.