Spectral property optimization for a narrow-band-filtered superfluorescent fiber source

The spectral broadening properties of a narrow-band-filtered superfluorescent fiber source (SFS) with different spectral shapes and spectral widths are analyzed numerically for the first time. Similar to other types of incoherent light, it is revealed that there exists a spectral broadening saturation phenomenon for the narrow-band-filtered SFS, and the output spectral width plus the stimulated Raman scattering effect could be reduced through using an active fiber with a higher group-velocity dispersion coefficient. Besides, both the spectral shapes and spectral widths have a significant effect on the spectral broadening property and the stimulated Raman scattering threshold of the narrow-band-filtered stimulated Raman scattering, and the filtered SFS with narrower spectral width will broaden faster during amplification. The results help to optimize the spectral properties of the filtered SFS to obtain a narrower spectral width at a specified output power. (letter)