Calculated pulse responses of perturbed fiber profiles

The effects of a central index dip and profile ripple on the total pulse width of a near-optimum optical fiber are analyzed. A comparison of our results, which are based on numerical integration of the scalar wave equation, with the results of the WKB method demonstrates that the WKB theory cannot be applied to rapidly varying refractive-index profile perturbations. Subsequently, we investigate the change in the pulse width resulting from strong mode coupling within each of the fiber's mode groups.