Brillouin and Rayleigh scattering in fiber waveguides: measurement of the angular distribution of the scattering intensities, scattering losses, and rotation of the plane of polarization

It is shown that Brillouin scattering can be used to investigate the angular dependence of the scattering and measure the inclination of the plane of polarization of the radiation inside a waveguide. Measurements were made in low-loss quartz-fiber waveguides which indicated that the scattering in these waveguides is of the Rayleigh type and that the scattering losses at 633 nm wavelength amount to ~ 11 dB/km. It is demonstrated that the small-angle scattering component in such waveguides is associated with the output of higher order modes and disappears when the distance from the entry to the waveguide is large.