Statistics of backscattering in optical waveguides

The statistics of backscattering induced by sidewall roughness in dielectric optical waveguides is experimentally investigated. We demonstrate that waveguide backscattering is a wavelength dependent random process, whose statistics follows the rules of single scattering systems, independently of shape, size and refractive index contrast of the waveguide, and of the light polarization state. The intensity of backscattering is distributed according to an exponential probability density function and its mean delay corresponds to a reflection at half the effective length of the waveguide.