Analysis of Long-Term Optical Effects in Double-Coated Optical Fibers Induced by Hydrostatic Pressure and Thermal Loading

The hydrostatic pressure and thermal loading simultaneously induced optical effects in double-coated optical fibers in the long-term are analyzed by the viscoelastic theory. Using the Laplace transformation method, close-form solutions for the microbending loss and refractive index changes are obtained. 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 the material properties of the primary and secondary coatings. To minimize the microbending loss and refractive index changes in the long-term, the Young's modulus of the primary coating, and the viscosity and Poisson's ratio of the secondary coating should be increased. Nevertheless, the viscosity and Poisson's ratio of the primary coating, and the Young's modulus of the secondary coating should be decreased.     

Transient thermal loading induced optical effects in tightly jacketed double-coated optical fibers with interlayer thermal contact resistance

This article investigates the transient microbending loss and refractive index changes in a tightly jacketed double-coated optical fiber subjected to thermal loading with stress-dependent interlayer thermal contact resistance. The effects of interlayer thermal resistance on the transient microbending loss and refractive index changes of the optical fiber are analyzed and discussed. Results show that the stress-dependent interlayer thermal contact resistance increases the lateral pressure induced by the transient thermal loading in the tightly jacketed double-coated optical fiber and, thus, the microbending loss. Similarly, the interlayer thermal contact resistance increases the thermal loading induced refractive index changes in the transient state of the loading.