New Gaussian-based approximation for modelling non-linear effectsin optical fibers

The use of Gaussian field approximations enables simple analytical models to be derived for non-linear fibers and doped-fiber lasers and amplifiers. A new Gaussian-based method is described that is as easy to use as the standard Gaussian approximations, yet provides an rms error in the confinement factor of only 1.1% for a wide range of matched-cladding fibers. Similar accuracy is obtained for depressed-cladding fibers. The new approximation is used to predict Raman gain in a typical experimental MCVD fiber and excellent agreement is obtained between theory and experimental measurements