Reconfigurable modal gain control of a few-mode EDFA supporting six spatial modes

Abstract

We experimentally demonstrate an inline few-mode erbium doped fiber amplifier supporting six spatial modes with reconfigurable differential gain control and excellent gain flatness obtained through mode-selective bidirectional pumping of a custom fiber with a radially profiled erbium dopant distribution. A signal gain of >20 dB was obtained for all the guided modes with a differential modal gain <2 dB and good gain flatness across the C-band. © 1989-2012 IEEE.