To improve the poor power conversion efficiency of L-band erbium doped fiber amplifier(EDFA),a new construction using a fiber Bragg grating(FBG) in an unpumped EDF section at the input side was proposed.Based on the Giles model with ASE,numerical simulation for the L-band EDFA was carried out.The influence of the Bragg wavelength and the reflectivity of the FBG to the characteristics of the designed L-band EDFA was studied.Experimental and theoretical results demonstrate that it can increase the small signal gain more than 3 dB.