Inelastic interchannel collisions of pulses in optical fibers in the presence of third-order dispersion

We study the effect of third-order dispersion on the interaction between two solitons from different frequency channels in an optical fiber. The interaction may be viewed as an inelastic collision in which energy is lost to continuous radiation owing to nonzero third-order dispersion. We develop a perturbation theory with two small parameters: the third-order dispersion coefficient d(3) and the reciprocal of the interchannel frequency difference 1/Omega. In the leading order the amplitude of the emitted radiation is proportional to d(3)/Omega(2), and the source term for this radiation is identical to the one produced by perturbation of the second-order dispersion coefficient. The only other effects up to the third order are shifts in the soliton's phase and position. Our results show that the statistical description of soliton propagation in a given channel influenced by interaction with a quasi-random sequence of solitons from other channels is similar to the description of soliton propagation in fibers with weak disorder in the second-order dispersion coefficient. (C) 2004 Optical Society of America.