Numerical study of single mode Er-doped microstructured fibers: influence of geometrical parameters on amplifier performances

A theoretical study of optimized single mode Er-doped MOFs designed for high efficiency amplification at 1550nm is carried out, deriving benefit from the demonstrated very low decrease of the overlap factor versus wavelength. In spite of this potential advantage, classical single mode MOFs are first shown to be less efficient than usual Er-doped step index fibers (SIF). However, novel single mode large core MOFs (LCMOFs) are designed, providing overlap factors higher than 0.9 at both the pump and the signal wavelengths. To obtain the same gain, the necessary length of LCMOF is reduced by up to 40% compared to that of Er-doped SIF. Such a highly efficient amplifying fiber is attractive for short pulse and soliton amplification.