Tailoring supercontinuum generation in a cascaded random Raman fiber laser based on a tunable noise pump.

The control of temporal noise of the pump could add an additional degree of freedom to manipulate the spectrum of continuous-wave (CW) pumped SC generation. In this paper, we experimentally tailor the CW-pumped supercontinuum (SC) generation in a cascaded Raman random fiber laser (CRRFL) based on a 1 µm pump with tunable temporal dynamics. The pump is based on a spectrally filtered ytterbium-doped random fiber laser (YRFL) seed laser, which can be amplified to a 10 W level with the tunable temporal noise. By increasing the detuning between the wavelength of a filter and the central wavelength of a YRFL, the temporal noise of the pump can be gradually increased, and we experimentally demonstrate the larger temporal noise of the pump can significantly enhance the spectral performance of SC generation in terms of spectral bandwidth and flatness. As a result, we realize the enhanced SC generation in a CRRFL with a more than doubled -10 dB bandwidth in a 50-km-long single-mode fiber by optimizing the temporal dynamics of the pump. We also demonstrate the enhanced output power of the spectral-optimized SC generation to 1.27 W with a shorter cavity length. We anticipate the combination of a tunable temporal noise ytterbium-doped pump and CRRFL could provide a new route to realize high-power, ultra-broadband, and smooth SC generation in a simple fiber cavity.