Multi-cascaded SBS in an optical fiber supported by Rayleigh backscattering

摘要

We performed numerical simulations in order to demonstrate that Rayleigh scattering - stimulated Brillouin scattering cooperative process (RS-SBS) can lead to generation of second-order SBS in standard telecom fibers. We give a clear physical insight into the RS-SBS mechanism and built 1 -D model describing dynamics of first two SBS cascades. To our knowledge for the first time, we theoretically determine the threshold of the second-order SBS generation in the RS-SBS process and reveal how the SBS spectra, phase portraits and power distributions along the fiber evolve as the pump power grows leading to growth of the second-order SBS. Recently published experimental observations of low-threshold second order SBS in 4.4-km-long optical fiber [e.g., J.Opt.Soc.Am.B 19, 2341-2345 (2002)] are completely reproduced by our simulations.