L-band superfluorescent fiber source(SFS) with (216 mW) output power under 1.668 W pump power is presented.The spectrum covers the broad wavelength range from 1 568 nm to 1 597 nm.High power double cladding Er~(3+)/Yb~(3+) co-doped fiber(EYDF) amplifiers are utilized in single pass and double pass configurations respectively to amplify lights from a low power L-band seed source.The results show that the double pass amplifier is superior to the single pass one in aspects of optical conversion efficiency and gain coefficient.The seed source has a function of suppressing laser oscillating and flattening the spectrum.