Characteristics Improvement of L-Band Superfluorescent Fiber Source Using Unpumped Erbium-Doped Fiber

An effective method for the improvement of the characteristics of an erbium-doped L-band superfluorescent fiber source (SFS) is demonstrated using an unpumped erbium-doped fiber (EDF). With a suitable length of unpumped EDF section in the single-forward pumped configuration, broadening of the L-band spectral linewidth is achieved and the variation of mean wavelength versus pump power is eliminated. A mean wavelength stable L-band SFS with a spectral linewidth of 50.2 nm and an output power of 60.2 mW is obtained experimentally. The method of using unpumped EDF enables one to offer a stable and wideband L-band SFS with high flexibility and to overcome the shortcomings of the synchronous pumping technique.