Generation of supercontinuum covering 520 nm to 2.25μm by noise-like laser pulses in an integrated all-fiber system

Supercontinuum (SC) is generated in an integrated all-fiber system, starting with a fiber laser. High-power laser pulses at the 1.56μm center wavelength are pumped into a hybrid nonlinear fiber, which consists of a highly nonlinear fiber (HNLF) fusion-spliced with a photonic crystal fiber (PCF). After the laser pulses propagate through an HNLF with a small dispersion slope of 0.0071 ps/nm²/km at 1.56μm wavelength, a supercontinuum covering a spectral range from 875 nm to 2.2μm is generated. Subsequently, a photonic crystal fiber (PCF) with a zero-dispersion wavelength (ZDW) at 1.04μm is used to expand the SC spectrum to the visible region. The relation between the center wavelength of the pulses and the ZDW of the nonlinear fibers matches the condition that is possible to induce strong soliton-related dynamics. In this study, it is experimentally found that noise-like pulses (NLPs) are more effective to generate ultra-broadband SC spectra than well-defined pulses (WDPs). The SC generated by pumping NLPs into a hybrid nonlinear fiber of an 8 cm HNLF and a 2 m PCF has an average power of 1.9 W and a spectrum covering a wavelength range from 520 nm to 2.25μm. The SC generated by pumping WDPs into the same hybrid nonlinear fiber has an average power of 1.85 W and a spectrum covering a wavelength range from 680 nm to 2.25μm.