Characteristics comparison of Er-doped double-pass superfluorescent fiber sources pumped near 980 nm

The Er-doped superfluorescent fiber sources (SFS's) pumped near 980 mm in double-pass forward and backward configurations are compared for the first time. The results indicate that a double-pass backward SFS is superior to the forward counterpart in many aspects: higher output power at various lengths of erbium-doped fiber, better pump-power dependent mean wavelength stability, and larger linewidths at various fiber mirror reflectance.