RESUMO
We experimentally analyze the stimulated Raman scattering characteristics of a high-birefringence fiber (HBF), which presents an extraordinary level of spectral broadening incurred by the strong nonlinear interaction between the pump and Stokes pulses via the polarization-mode dispersion and group-velocity dispersion of the fiber. We also investigate the impact of the inter-pulse time-delay on the additional spectra broadening when dual-wavelength pump pulses are used. Exploiting these unique SRS properties of the HBF, we develop a novel Raman continuum source based on an all-fiber dual-wavelength master-oscillator power amplifier that can generate a dip-free spectrum in the 1200-1400-nm spectral range. We finally obtain a broadband continuum having an average power of ~840 mW and a 3-dB bandwidth of ~240 nm centered at 1200-1400 nm, which also represents a good spectral flatness and conversion efficiency. This type of source is very useful and important for optical coherence tomography applications, for example.
