Thermally and mechanically induced microbending losses in single-coated optical fibres in the long term

The thermally and mechanically induced microbending losses in single-coated optical fibres in the long term are investigated by the viscoelastic theor y. The microbending loss is dominated by the compressive radial stress at t he interface between the glass fibre and the polymeric coating, which is a function of the material properties of the polymeric coating and its thickn ess. To minimize the thermally and mechanically induced microbending losses in the long term, the radius, Young's modulus, thermal expansion coefficie nt and relaxation time of the polymeric coating should be decreased, but th e Poisson's ratio of the polymeric coating should be increased. Additionall y, based on strength consideration, the radius and Young's modulus of the p olymeric coating should be thick or hard enough to support the mechanical s tresses.