Continuous-wave pumping in the anomalous- and normal-dispersion regimes of nonlinear fibers for supercontinuum generation

• Published in: Optics letters 2005, Vol.30 (1), p.61-63
• Main Authors: ABEELUCK, Akheelesh K, HEADLEY, Clifford
• Format: Article
• Language: English
• Subjects: Beam trapping, self-focusing and defocusing; self-phase modulation; Beam trapping, self-focusing, and thermal blooming; Exact sciences and technology; Fundamental areas of phenomenology (including applications); Nonlinear optics; Optics; Phase conjugation, optical mixing, and photorefractive effect; Phase conjugation, optical mixing; photorefractive and kerr effects; Physics; Stimulated raman scattering; cars
• ISSN: 0146-9592; 1539-4794
• DOI: 10.1364/ol.30.000061

Supercontinuum (SC) growth in highly nonlinear fibers is compared for cw pumping in the anomalous- and normal-dispersion regimes. For anomalous-dispersion pumping, the combined effects of modulation instability (MI) and stimulated Raman scattering (SRS) contribute to spectral broadening. Furthermore, breakup of the cw light into ultrashort pulses by MI leads to the formation of a Raman pulse that evolves into a soliton, as evidenced by the observation of soliton self-frequency shift. Blueshifted, nonsolitonic radiation associated with the fission of higher-order solitons is also present in the SC spectra. For normal-dispersion pumping, SRS seeds the SC growth by generating several cascaded Stokes orders. When the Stokes orders are shifted into the anomalous-dispersion regime at higher launch powers, MI again causes soliton formation. Broadband continua are generated when the laser is positioned as far away as 191 nm from the zero-dispersion wavelength in normal dispersion.