Effect of nonlinearity and dispersion on pulse propagation in optical fibers.

Pulse propagation in optical fibers is considered after including the effects of both dispersion and nonlinearity. To estimate the extent of pulse broadening, an analytic expression for the pulse width is obtained under certain simplifying assumptions. Its range of validity is discussed by comparing the analytical prediction to the numerically calculated pulse width. Results are presented for 1.55micron optical pulses propagating in conventional as well as in dispersion shifted fibers. Our results show that for relatively wide pulses the nonlinearity broadens the pulse considerably over the linear case, thereby reducing the band width of optical communication systems operating at the zero-dispersion wavelength. For sufficiently short pulses we have found that the nonlinearity can give rise to pulses narrower than the linear case.