Distributed fiber-optic strain sensor by localizing dynamic grating in polarization-maintaining erbium-doped fiber: Proposal and theoretical analysis

A novel scheme of distributed fiber-optic strain sensor by localizing a dynamic grating in a polarization-maintaining erbiumdoped fiber is proposed. The dynamic grating, which is introduced by launching two counterpropagating coherent light beams into a pumped erbium-doped fiber per gain saturation, is examined. A theoretical model of the dynamic grating is given and used to perform simulations of the reflectivity of the dynamic grating localized by synthesizing the optical coherence function. Theoretical analysis and numerical simulation of the novel sensor scheme show that the Bragg frequency of the dynamic grating will shift according by 0.426NIHz/mu epsilon to strain in a typical polarization-maintaining erbium-doped fiber.