SUPPRESSION OF THE SOLITON FREQUENCY-SHIFTS BY NONLINEAR PAIRING OF PULSES

The combined effects of interpulse Raman scattering and cross phase mo dulation from a pump pulse on the propagation of picosecond signal pul ses in an optical fiber is studied. It is shown that although interpul se Raman scattering can suppress the frequency downshifts, it is XPM t hat has a more significant effect. A new expression for XPM in the pre sence of Raman scattering is derived. The copropagation of a bright an d dark pulse in the so-called reverse or inverted case, in the presenc e of Raman scattering is also studied. A dark pulse is seen to stabili ze the bright pulse against the frequency downshifts.