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 in duced in the transmitted wave as wed as in the backward Brillouin wave . In fibers where the Brillouiu gain spectra consist of several resona nces, the induced intensity noise of the transmitted wave has a wide s pectrum and it may be the dominant noise in the receiver for a broad r adio frequency band (0-1 GHz). This unexpected result is explained by a multiple scattering process which is caused by stimulated and by the rmally excited phonons. The SBS induced noise may cause a performance degradation in analog optical systems which require high optical power s and low noise, Using fibers with a single Brillouin resonance map li mit the noise to lower frequencies.