Analyses of soliton interactions by means of a perturbed inverse-scattering transform

Interactions of solitons generated by a pair of optical pulses in a fiber having bandpass filters, nonlinear amplifiers, sliding filters, and with the self-induced Raman effect are studied numerically by using the perturbed nonlinear Schr\"odinger equation, and analytically by the perturbed inverse-scattering transform developed by Kaup and Newell [Proc. R. Soc. London Ser. A 361, 413 (1978)] and Karpman and Maslov [Zh. Eksp. Teor. Fiz. 73, 537 (1977)]. The results are also compared with these obtained by the quasiparticle approach developed by Karpman and Solove'v [Physica D 3, 487 (1981)].