Measurement of optical waveguide scattering loss: an improved method by the use of a Coblentz mirror.

Light scattered from optical waveguides is collected by a Coblentz mirror, which provides a stable, accurate, and relatively high signal-to-noise ratio measurement. The scattering loss of the waveguides is analyzed from the measured scattered-light-power distribution functions, and the results show that the attenuation coefficients of the waveguides can be expressed by the derivative of these scattered-light-power distribution functions, which can be calculated from a least-squares fit to the measured scattered-light-power distribution functions.