“…To describe the simultaneous transmission of pulses of different wavelengths in a single-mode optical fiber in the absence of the four-wave mixing (FWM), we follow the standard derivation [6], [7], and obtain a system of incoherently coupled NLS equations in the coordinate system moving with the group velocity of the central pulse (1) where For a th pulse, is the slowly varying envelope measured in the units of , where is the incident power carried by the central pulse, is the normalized group velocity dispersion, is the relative group velocity mismatch, and characterizes the nonlinearity strength . The time and propagation distance are measured in units of characteristic pulsewidth ps, and dispersion length km [3], [4], [5]. For the operating wavelengths spaced 4-5 nm apart (to avoid the FWM effect), within the band 1530-1560 nm (see [3], [4], [5]), the coefficients and are different but close to one.…”