The calculated group velocity dispersion curves for the fundamental mode of PM-PCF with two zero dispersion wavelengths along the fast axis of 769 nm and 929 nm and the slow axis of 794 nm and 887 nm are presented in Fig.
Taking into account the Kerr and Raman contributions to the nonlinearity, the self-steepening (SS), the loss of pump field, the influence of the wavelength-dependent effective mode area, and the fourth-order group velocity dispersion, the simulation results using the nonlinear Schrodinger equation (NLSE) [31,32] can exactly predict the evolution of femtossecond pulses inside a span of PM-PCF with a length of 55 cm for the pump wavelength of 785 nm and the average power of 300 mW.
Investigations demonstrated that the spectrum decomposition technique enables with some uncertainties to reconstruct the segments of the group velocity dispersion curves.
Reconstruction of the group velocity dispersion curve according proposed technique  is performed in the following steps:
z], from which the group velocity dispersion, [[beta].
Russell, "Experimental measurement of group velocity dispersion in photonic crystal fibre," Electronics Letters, Vol.
In this case, the quality of the data after passing through the grating is distorted due to delay in the signal which is also called the group velocity dispersion broadening and deformations of the data pulse and Inter Symbol Interference (ISI) in the neighboring and distance time slot.
Figure 1 shows the reflectivity, phase spectra and group velocity dispersion (GVD) of a uniform grating while refractive index profile variation is step index.
The velocity model down to a depth of about two kilometers is inverted from the average group velocity dispersion
curve of Rayleigh waves.
5 are the overlaps of experimental group velocity dispersion
curves on the theoretical one.
For the surface wave tomography, we first need to measure the group velocity dispersion
Group velocity dispersion
of the Rayleigh waves represents the structural change in the porous ground coat.