Evolution of hyperbolic-secant optical pulses towards wave breaking in quintic nonlinear fibers

Evolutions of the frequency chirps, shapes, and spectra of initial hyperbolic-secant pulses towards wave breaking are numerically investigated in the normal dispersion regimes of optical fibers with quintic nonlinearity and the developing chirps and the characteristic distances of wave breaking are analytically processed approximately. The results show that quite different mathematical expressions from those of initial Gaussian pulses are obtained. Moreover, the wave breaking here will be more intense for more oscillation peaks will appear in the pulse wings and the breaking process will last longer distance before rectangle-shaped pulses form at last. However, the quintic nonlinearity plays a similar role to the case of initial Gaussian pulses in developing chirps and bringing forward or retarding the wave breaking. The wave breaking distance will also decrease with increase of the quintic nonlinearity and the soliton order.

► In case of quintic nonlinearity, the frequency chirp is deduced and calculated.
► Then, the critical distance (CD) for wave breaking (WB) is deduced and calculated.
► Shape and spectral evolutions towards WB are numerically calculated.
► In comparison, the wave breaking here is more intense than that of the Gaussian pulse.
► The larger the quintic nonlinearity and soliton order, the shorter the CD.