Hydrostatic pressure and thermal loading induced long-term optical effects in tightly jacketed double-coated optical fibers

Abstract

By the viscoelastic theory, the hydrostatic pressure and thermal loading simultaneously induced optical effects in tightly jacketed double-coated optical fibers in the long term are analyzed. Using the Laplace transformation method, close-form solutions for the microbending loss and refractive index changes are obtained in the transform domain. The results of the microbending loss are initially identical to those obtained by the elastic analysis, and then decrease gradually as time progresses. The microbending loss and refractive index changes of the glass fiber are functions of material properties of the coating layers and jacket. To minimize the microbending loss and refractive index changes in the long term, the viscosity ratio η3/η1, Young’s modulus ratio E2/E1 and E3/E1, and ratio of Poisson’s ratio ν3/ν1 should be increased. Nevertheless, the ratio of Poisson’s ratio ν2/ν1 should be decreased.