Thermal stresses in tightly jacketed double-coated optical fibers at low temperature

Abstract

The thermal stresses in tightly jacketed double-coated optical fibers at low temperature have been analyzed by the thermoelastic approach. The lateral pressure and normal stresses in the glass fiber, primary coating, secondary coating, and jacket have been derived. The thermal stresses in the optical fibers are affected by the temperature difference, material properties of polymeric coatings, and their thicknesses. It is possible to select the suitable polymeric coatings to produce a minimum lateral pressure in the glass fiber. The microbending loss is dominated by the lateral pressure in the glass fiber. To minimize such a microbending loss, the Poisson’s ratio of the primary and secondary coatings, and the Young’s modulus of the jacket should be increased. On the other hand, the Young’s modulus of the primary coating should be decreased. However, the thickness of the primary coating, and the thickness and Young’s modulus of the secondary coating exist the optimum values. The glass transition temperature of the primary coating should be lower than the temperature ranges under consideration. The thermal stresses for plane strain and zero axial force conditions are also discussed.