IMPROVED SOLITON-EFFECT PULSE-COMPRESSION BY COMBINED ACTION OF NEGATIVE 3RD-ORDER DISPERSION AND RAMAN SELF-SCATTERING IN OPTICAL FIBERS

By numerically solving the generalized nonlinear Schrodinger equation, we show that soliton-effect compression of ultrashort pulses in optic al fibers can be significantly improved by use of the combined effect of negative third-order dispersion and Raman self-scattering. The effe ct of Raman self-scattering leads to redshifting of the pulse spectrum , whereas negative third-order dispersion tends to broaden the redshif ted spectrum, which results in a significant increase of both the opti mum compression ratio and the peak power of the compressed pulse. We a lso show that, for a given input pulse, there is an optimum negative t hird-order dispersion at which the improvement in the pulse compressio n is maximum and that there exists a range of initial pulse widths onl y within which can the improvement in pulse compression take place. (C ) 1998 Optical Society of America.