L-band erbium-doped fiber amplifier incorporating an inline fiber grating laser

Wide-band erbium-doped fiber amplifiers (EDFAs) having an inherently flat gain spectrum in the long-wavelength-band (L-band) between 1570 nm and 1600 nm have recently been realized. The L-band amplification has been achieved by simply using a longer length of EDF than in the conventional-wavelength-band (C-band) EDFAs, In this paper, we investigate the improvement of the gain flatness in an L-band EDFA co-pumped with the high-power pump light at 1.48 mum and the medium-power auxiliary pump light at 1.55-1.565 mum, We also propose a novel L-band EDFA incorporating an inline fiber grating laser (FGL) operating at the auxiliary pump wavelength, and demonstrate that the proposed EDFA has better gain flatness as well as the gain clamping characteristics.