The polarization dependent performance of EDFA has been explained in terms of polarization hole burning, considering that the erbium sites in the silica matrix preserve its random nature. Although typical EDFAs are built with an erbium fiber longer than 10 m (hence the active fiber is necessarily wound) the influence of the bending has not been included in the investigation of this effect. To verify the relevance of bending induced birefringence, a helically- wound active fiber has been used to build an EDFA. The characterization of this helically-wound optical amplifier has shown that the polarization dependent performance was enhanced. The stronger link between the states of polarization of the signal wave, the pump wave and the active fiber birefringence axes was used to show that a selective excitation of the erbium ions by a polarized pump and a selective de-excitation of those ions by a polarized signal are the origin of the polarization dependent performance of EDFAs.

Date Published: 1 April 1999
PDF: 5 pages
Proc. SPIE 3622, Rare-Earth-Doped Materials and Devices III, (1 April 1999); doi: 10.1117/12.344503

Published in SPIE Proceedings Vol. 3622:
Rare-Earth-Doped Materials and Devices III
Shibin Jiang; Seppo Honkanen, Editor(s)