Non-Gaussian intensity distribution and dispersion compensation in single-mode fibres

In the letter it is shown that the Gaussian approximation for the fundamental mode of a typical quadruple-clad fibre does not lead to the observed dispersion behaviour. The calculations indicate that the non-Gaussian shape of the intensity distribution and the dispersion compensation are closely related. The experiments can be explained by assuming that the fundamental mode is a superposition of two Gauss functions.