We measure the waveform and phase curves of short optical pulses before and after transmission over different lengths of fibers by use of the pulse analyzer with the frequency-resolved optical gating (FROG), and numerically simulate pulse evolution under the experimental conditions.The nonlinear coefficient of the fiber is given by comparing the experimental results with the numerical ones.Difference between the experiment and numerical simulation is analyzed.
We propose the sub-picosecond chirped soliton pulse propagation in concave-dispersion-flattened fibers(CDFF).The effects of pulse characteristics and the fiber dispersion parameters on propagation characteristics of the chirped soliton pulse are numerically investigated in the CDFF by the split-step Fourier method(SSFM).The unchirped soliton pulse can stably propagate with unchanged pulse width in the CDFF.The temporal full width at half maximum(FWHM) of the chirped soliton performs a damped oscillation with the increase of propagation distance.The period and amplitude of theoscillation increase with the increase of the chirp parameter |C|.The effect of high-order dispersion(β3-β6) on soliton propagation characteristics can be neglected.The soliton pulse slightly broadens with the increase of propagation distanceand still maintains soliton characteristics when the fiber loss(ATT) is further considered.The variation of root-meansquare(RMS) spectral width with propagation distance is opposite to that of the temporal width.The output spectrum of soliton has a single peak for the unchirped case,while has multi-peak for chirped case.The temporal width of the soliton obviously increases with the increase of the initial width,decreases with the increase of dispersion peak D0 of the fiber,and slightly increases with the decrease of dispersion coefficients k1 and k2 of the fiber.
