Theory and measurement of Young's modulus radial profiles of bent single-mode optical fibers with the multiple-beam interference technique

Multiple-beam Fizeau fringes in transmission have been applied to the study of the nonlinear stress-strain relationship due to bending in the cladding of single-mode optical fibers. The present study yields a relation between the variation of refractive indices of Gent single-mode fibers, represente d by the fringe shift, and the nonlinear radial change of Young's modulus a long the fiber cross section. Experimentally, the study confirms the nonlin ear asymmetric stress-strain relation across the fiber cross section. This relation is due to the asymmetric distribution of the compression and tensi le stresses over the fiber cross section rather than to the shift in the ce ntroid (neutral axis). (C) 2001 Optical Society of America.