The influence of acoustic-wave diffraction on nonstationary backward stimulated Brillouin scattering (SBS) in the presence of feedback for a Stokes electromagnetic wave is numerically investigated. The cases of an acoustic-waveguide and-antiwaveguide fibers are considered. The Kerr nonlinearity is taken into account. For fibers with a small core radius (r<sub>0</sub><3 μm), the influence of sound diffraction on the nonstationary SBS can lead to new features. The importance of the acoustic-mode structure of the fiber for the process of forming a pulse train is shown in the case of synchronous pumping in Brillouin fiber lasers. It has been found that the acoustic-antiwaveguide fibers with a small core, r<sub>0</sub><3 μm, can be preferable for obtaining a stable train of compressed pulses. Under a constant input pump, an acoustic diffraction can essentially reduce the threshold of the modulation instability under SBS in the presence of the feedback.
© 2002 Optical Society of America
(190.3100) Nonlinear optics : Instabilities and chaos
(190.4370) Nonlinear optics : Nonlinear optics, fibers
(190.5890) Nonlinear optics : Scattering, stimulated
(290.5900) Scattering : Scattering, stimulated Brillouin
V. Grimalsky, S. Koshevaya, G. Burlak, and B. Salazar-H., "Dynamic effects of the stimulated Brillouin scattering in fibers due to acoustic diffraction," J. Opt. Soc. Am. B 19, 689-694 (2002)