Intrinsic Perturbation by Thermal Stress Birefringence and PMD

Abstract

Birefringence and polarization dispersion introduced by thermal stress in single-mode fibers with elliptical core are formulated in terms of fiber structure parameters, thermal expansion coefficients, and thermo elastic constants. Thermal stress distribution and birefringence characteristics are estimated within first-order perturbation with respect to fiber core ellipticity. Normalized frequency dependence of birefringence and polarization dispersion is also derived in this analysis. Birefringence and polarization dispersion in elliptical core fiber are seen to depend on thermal stress rather than geometrical anisotropy for relatively small relative index differences. Numerical examples are presented for germanosilicate, borosilicate, and phosphosilicate glass fibers