Few mode Er3+-doped fiber with micro-structured core for mode division multiplexing in the C-band

Design and experimental characterization of Er3+-doped fiber amplifiers supporting 6 spatial modes in wavelength division multiplexing regime are reported. The study is first focused on Er3+-doped circular ring-structured profiles accessible with conventional fiber manufacturing techniques. However, these fiber designs, optimized for gain equalization, prove to be difficult to obtain experimentally. So as to go beyond these limits, an alternative approach based on a "pixelated" Er3+-doped core is proposed. Several possible designs are theoretically investigated and a first fabrication of micro-structured fiber is presented. (C) 2013 Optical Society of America