Abstract: In order to obtain high performance S+C+L optical fiber light sources with ultra bandwidth and taking a new hybrid-doped optical fiber as transmission medium and taking laser diodes pumping thulium-doped and Er-doped optical fibers,with two 3dB wide band couplers as the optical fiber reflector,a new fiber laser was designed and its energy was controlled stable with the help of a power control circuit.Experiments and the theoretical analysis were carried out.The total output was 28mW with bandwidth from 1460nm to 1610nm in the S+C+L wave band.The experimental results indicate optical-fiber-loop mirrors not only improve the flatness of the light source but also enhance the light-to-light conversion efficiency greatly.