GUIDING-CENTER SOLITON IN OPTICAL FIBERS

For a relatively long optical pulse in a fiber with a dispersion distance z0 much larger than the loss distance, a soliton cannot exist in an ideal sense. However, with a proper choice of the initial amplitude and amplifier distance z(a), a nonlinear pulse (a guiding-center soliton) propagates like a soliton over a distance much larger than the dispersion distance when it is periodically amplified at distances much shorter than the dispersion distance. the guiding-center soliton is shown to satisfy the nonlinear Schrodinger equation with a correction of order (z(a)/z0)2. Numerical examples supported by analytical results are presented for distortionless propagation of the guiding-center solitons with a pulse width of 40 psec in a dispersion-shifted of D = 1 psec/(nm-km).