Determination of the optical characteristics of multimode fiber waveguides by backscattering

A system is described for measuring the optical characteristics of multimode fiber waveguides at λ = 0.53 μ by backscattering. The losses determined by this method showed good agreement with those measured by the break method. The difference between the refractive index values at wavelengths of 0.53 μ and 1.06 μ was also measured for a borophosphorosilicate waveguide and was found to be 0.022.