A ray theory of light backscattering from an optical fiber of arbitrary refractive-index profile in the rainbow region is presented. The backscattered light field is expressed in terms of Airy function and its first derivative, and is uniformly valid throughout the rainbow region. Thus this theory is called the uniform approximation approach. The theory gives results in excellent agreement with those from the wave theory but it has the advantage of providing us with a better understanding of the scattering process and is also less time consuming in computation. Numerical results of backscattered light patterns from five different fibers are given.
© 1978 Optical Society of AmericaPDF Article