Hybrid birefringence and dichromatism in twisted single-mode erbium-doped fibers

摘要

In this work we present an experimental evaluation of the twist-induced birefringence changes measured in straight samples of commercial single-mode erbium-doped fibers. The five commercial samples studied showed a significant asymmetric response to right and left twists, a result different to that previously measured in standard telecom fibers. We found similar birefringence responses measured for fibers with different erbium concentrations, developed by the same manufacturer; while fibers made by different manufacturers presented a non-similar response. Since absorption is an important characteristic of erbium-doped fibers, we have considered the possible influence of hybrid (linear and circular) dichroism. Therefore, we calculated the 4x4 Mueller matrix required to predict the induced birefringence taking into account refractive and absorption anisotropies.