Using Reverse Saturable Absorption to Boost Broadband Noise-Like Pulses

Utilizing the nonlinear effects in a photonic crystal fiber to broaden the spectrum and reverse saturable absorption to further improve the flatness of the spectrum, ultra-broadband noise-like pulses (NLPs) were produced in a fiber laser. Guided by numerical results, a broadband spectrum with 290 nm 3-dB bandwidth was obtained, which, to the best of our knowledge, is the broadest bandwidth achieved for NLPs. Spectral degradations of the NLPs have also been observed, and are discussed.