We obtained stable narrow bandwidth superfluorescent sources with central wavelengths at 1060 nm and 1078 nm by using a segment of ytterbium-doped double-cladding fiber as the gain medium, multi-mode diode lasers operating at 976 nm and 915 nm as pumping sources, and fiber Bragg gratings as filters. Two three-stage high power fiber amplifier systems are used to boost the output power up to 57.4 W and 56.6 W respectively with the slope efficiencies of 66.6% and 66.7%. The superfluorescent bandwidths at 1060 nm and 1078 nm are 0.05 nm. Two output beams are spectrally combined with a transmission diffraction grating, the output beam is with the power of 104.2 W, power efficiency of 91.3% and the beam quality M² is superior to 1.7.