Erbium-Doped Fibers Improvement For Optical Amplifier Modules

Erbium-doped fiber amplifiers (EDFA) are very attractive for all optical long span transimissions in the third telecommunication spectral window. Recently, over 2000km repeaterless transmission experiments have been performed with EDFA [1]. Two pump wavelengths appear truly excellent because of their very high performances and laser diode pumping feasibility : 1.48μm and 0.98μm, each of them having its own specificity [2]. Today’s best reported pump efficiency are 2.6dB/mW for color center laser pumping near 1.48μm [3] and 4.9dB/mW for a 0.98μm laser diode pumped amplifier [4]. The increase of the last year published EDFA performances clearly demonstrate that we may be far from optimized fibers.