Soliton-effect compression and dispersive radiation

Soliton-effect pulse compression is investigated using two approximate methods which do not include the dispersive radiation shed as the soliton evolves and by one approximate method which does. Results derived from the approximate equations are compared with full numerical solutions of the governing equation. It is found that while the methods without radiation can,br used to predict the position of optimal compression, to also have accurate prediction of the pulse amplitude requires inclusion of the dispersive radiation. A careful analysis of the solutions of the various approximate equations shows that care must be taken in using length predictions derived from approximate methods. This is because there are phase differences between the numerical and approximate solutions, Such phase differences are not predicted by the approximate methods. While approximate methods do exist to determine phase evolution, these methods do not predict the initial phase, which is of importance when distance predictions are made. (C) 2000 Elsevier Science B.V. All rights reserved.