Abstract

Although stimulated Raman scattering (SRS) is a frequency downshifted process that can turn optical fibers into several devices, it can also be detrimental to optical transmissions because of Raman-induced crosstalk in wavelength-division multiplexing (WDM), cross-phase modulation or soliton self-frequency shift processes¹. It thus limit the power level used in fiber communications links. The stimulated Raman threshold can be increased via parametric suppression¹, where the coupling between growing phase-matched four-wave mixing (FWM) sidebands inhibits the growth of Raman Stokes scattering. This situation is efficient if the parametric frequency shift does not lie within the Raman gain bandwidth. Recently, the orthogonal component of the Raman gain has been used for SRS suppression in anyone of the axes of a birefringent fiber, under dual­frequency cross-polarization pumping². In the present work, we used the antisymetry of the Raman susceptibility for demonstrating the SRS suppression under a single-polarization dual-frequency pump scheme, with no appearance of phase-matched FWM sidebands.

© 1998 IEEE