Broad-band transmitted intensity noise induced by Stokes and anti-Stokes Brillouin scattering in single-mode fibers

We experimentally investigate the optical noise induced by stimulated Brillouiu scattering (SBS) in single-mode fibers. The noise, which is caused by the random nature of spontaneous Brillouin scattering, is induced in the transmitted wave as wed as in the backward Brillouin wave. In fibers where the Brillouiu gain spectra consist of several resonances, the induced intensity noise of the transmitted wave has a wide spectrum and it may be the dominant noise in the receiver for a broad radio frequency band (0-1 GHz). This unexpected result is explained by a multiple scattering process which is caused by stimulated and by thermally excited phonons. The SBS induced noise may cause a performance degradation in analog optical systems which require high optical powers and low noise, Using fibers with a single Brillouin resonance map limit the noise to lower frequencies.