Diana Tentori

Due to its microstructure, photonic crystal fibers present wavelength regions with polarization-dependent loss, an aspect not observed in conventional fibers. We include this fact in their polarization characterization. In this research, the use of polarimetric methods to two different types of large-mode-area microstructured fibers has shown that both samples exhibited elliptical birefringence with residual torsion. We present the modifications required to perform the evaluation and justify its theoretical bases.

We present an analysis of polarization evolution which includes the birefringence caused by the torsion of the fiber due to the coiling. Results show that a phase shift in Faraday’s angle is introduced.

The output polarization state of a liquid core single-mode fiber was evaluated. Its variation with the temperature change induced by the light traveling along the core indicates it can be used as a polarization scrambler.

We present an experimental arrangement allowing the direct measurement of the amplified spontaneous emission PDG generated in the EDFA. PDG values were low and the degree of polarization of signal and pump was not degraded.

The residual birefringence of weak guidance single mode fibers (standard, erbium-doped or photonic) has two main contributions: homogeneous retardation and torsion, whose polarization effects on a signal can be minimized using two non-parallel helical windings.

In this work we analyze the birefringence matrix developed for a twisted fiber in order to identify the basic optical effects that define its birefringence. The study was performed using differential Jones calculus. The resultant differential matrix showed three independent types of birefringence: circular, linear at 0 degrees and linear at 45 degrees (Jones birefringence). We applied this birefringence matrix to the description of the output state of polarization measured for three commercial fibers that due to its higher rigidity present stronger birefringence changes when twisted. The torsion applied to the erbium-doped fiber samples varied from 0 to 1440 degrees.

We describe a simple and precise experimental procedure for the detection of the transverse fluorescence emitted by excited ions in erbium-doped fibers. The modulation of the optical pump (980 nm) power allows distinguishing between transverse fluorescence and pump radiated modes in the measured optical signal using a broadband InGaAs detector.

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 4×4 Mueller matrix required to predict the induced birefringence taking into account refractive and absorption anisotropies.© (2011) COPYRIGHT Society of Photo-Optical Instrumentation Engineers (SPIE). Downloading of the abstract is permitted for personal use only.