A high-power broadband light source covering C-band and L-band (1520～1610 nm) by using two kinds of different concentration erbium-doped fiber was reported in this paper. In the dual-stage double-pass structure, the double-pass forward pumping was used in the first stage, the fiber of lower doped concentration was 7.5 m, and the output of first stage was used as seed signal; in the second stage, backward pumping was used, and the fiber of much higher doped concentration was 31.2 m. The fiber loop reflector was used to enhance the conversion efficiency of pumping LD, and high output power and good flatness were also achieved. After matching the pumping power of the two stages, the amplified spontaneous emission (ASE) source with the high output power of 19.20 mW (12.83 dBm) and with the mean wavelength of 1552.82 nm was developed and obtained. Meanwhile, the relation between the output and the change of pumping in the configuration was discussed implicitly, it was important to the design of the source.