We analyze stimulated Raman scattering in normally dispersive highly birefringent fibers under dual-frequency, orthogonal polarization pumping. Experiments show that stimulated Raman scattering can be suppressed in anyone of the fiber axes by two distinct processes prevailing at large and small group-velocity mismatches (GVM’s), respectively, between the pumps. For a relatively large GVM, parametric four-wave mixing is the dominant process for the suppression of Raman–Stokes radiation. On the other hand, for a small GVM, the Raman–Stokes light is suppressed along the polarization direction of the highest-frequency pump, through a mechanism associated with the orthogonal component of the Raman gain. The sign of the GVM between the pumps allows for selecting the particular fiber axis where suppression of the Raman–Stokes radiation is desired. This selection is achieved by simply tuning the frequency spacing between the pumps.
© 1998 Optical Society of America
(060.2310) Fiber optics and optical communications : Fiber optics
(190.4380) Nonlinear optics : Nonlinear optics, four-wave mixing
(260.1440) Physical optics : Birefringence
(290.5860) Scattering : Scattering, Raman
P. Tchofo Dinda, G. Millot, and S. Wabnitz, "Polarization switching and suppression of stimulated Raman scattering in birefringent optical fibers," J. Opt. Soc. Am. B 15, 1433-1441 (1998)