A kind of widebandwidth optical source applying amplified spontaneous emission of Er3+doped optical fiber is proposed, with bidirectional pumping and doublepass configuration. Experiments were performed to verify the proposed scheme, and then the output performance was optimized. The pump efficiency, spectrum flatness and stability were analyzed in detail. The experimental results show that the pump conversion efficiency is increased by 8.24%, the flatness of optical spectrum is improved by 1dB in 1525~1557nm without any filter，and the output linewidth @3dB is widened by 24.56nm. The stable output of optical power and spectrum within one hour is realized, which can provide light source for optical fiber sensing, spectral analysis, etc.