Effects of initial overlap on the propagation of optical solitons at different wavelengths

Effects of initial overlap between two solitons at different carrier wavelengths are studied theoretically and numerically as a function of the degree of overlap and the frequency separation of the two carriers. When the two solitons are fully overlapped, the carrier frequencies of the emerging two solitons are shifted toward each other by an amount proportional to the initial power and inversely proportional to the initial frequency separation with little effect on their amplitudes provided that the frequency separation is sufficiently larger than the spectral width of the solitons.