Complete determination of stress in fiber preforms of arbitrary cross section

Tomographic measurement of femtosecond-laser induced stress changes in optical fibers

“…In the focus region, the peak stress increase is 6.2 kg/mm 2 . completely. 12 This allows separating the photoelastic contribution from the total refractive index change. 15 Figure 3͑a͒ shows the stress-induced index change for the x component, Fig.…”

“…The knowledge of the axial stress distribution zz allows calculation of the other components ( rr , , r ) of the stress tensor. 12 Further, photoelasticity relates the stress tensor to the refractive index tensor, 11 so the stress-induced component of the total refractive index change can be evaluated from stress measurements. Figure 1 shows the two-dimensional axial stress profile Fig.…”

Drawing parameters optimization for birefringence reduction in optical fibers

“…The numerical algorithm was tested both on a numerical model of a polarization-maintaining (PM) fiber and on actually measured phase projections on a PM fiber and it was verified that recovered stress components well agreed with those in [6,16]. Once all tensor stress components of the characterized SMF fibers were derived the corresponding stress-induced birefringence b and beatlength L b were estimated following the variational formulation-based vec- tor perturbation model reported in [2,6], as shown in Table 2.…”

“…To evaluate how differences in asymmetric stress distributions affect fiber intrinsic birefringence, all the stress tensor components were first mathematically derived from measured r zz , exploiting the mathematical formalism described by Puro and Kell [16]. The numerical algorithm was tested both on a numerical model of a polarization-maintaining (PM) fiber and on actually measured phase projections on a PM fiber and it was verified that recovered stress components well agreed with those in [6,16].…”

Faraday rotation influence factors in tellurite-based glass and fibers

“…Besides the magneto-optical property, requirements are also critical on T g (DT g = T g cladding -T g core \ 30°C) and a difference (Da = a cladding -a core \ 2.0 9 10 -6 /°C), and the gradient of Da introduces thermal stress, which creates radial birefringence. A matchable thermal property (proper Da) is good not only for fiber fabrication, but also for reducing thermal stress in fiber, because the birefringence greatly degrades the MO property [22][23][24]. In addition to Da, differences in the viscosity between different regions of a fiber induced by DT g can interact with the fiber draw process to yield elastic stresses and strains in room temperature optical fibers [25,26].…”