On the formation of solitary and periodic waves in optical fibres near the zero-dispersion point

A spectral method is used to investigate nonlinear wave propagation in optical fibres near the zero-dispersion point. The conditions for solitary (bright and dark) or periodic wave generation and propagation without any distortion, as well as the form of the waves, are obtained. It is demonstrated that bright solitary pulses may propagate near the second zero-dispersion point in quadruple-clad fibres, while neither periodic nor solitary wave propagation is practically possible near the sole zero-dispersion point in graded-index fibres, or near the first one in quadruple-clad fibres.