The group velocity dispersion is the group delay dispersion per unit length. The basic units are s2/m. For example, the group velocity dispersion of silica is +35 fs2/mm at 800 nm and −26 fs2/mm at 1500 nm. Somewhere between these wavelengths (at about 1.3 μm), there is the zero-dispersion wavelength.
Effects of Group Velocity Dispersion (GVD) on Gaussian Pulse Propagation. The results for the output pulse shape and chirp are presented in Figure 7. It can be seen that an exact compensation between the dispersion induced and initial chirp occurs, and that the peak power of …
Group Velocity. Due to chromatic dispersion, the group velocity in a medium is in general different from the phase velocity (typically smaller than the latter), and it is frequency-dependent; this effect is called group velocity dispersion . The difference between group velocity and phase velocity also changes the carrier–envelope offset of the pulse.
Technical Note: The Effect of Dispersion on Ultrashort Pulses. Dispersion in materials is defined by the group velocity dispersion. In order to estimate amount of GDD introduced by a material of length L, one has to calculate the wavelength dependent index of refraction, n(λ), typically in …
If the derivative term is zero, group velocity equals phase velocity. In this case, there is no dispersion. Dispersion is when the distinct phase velocities of the components of the envelope cause the wave packet to “spread out” over time.
Group Velocity Dispersion Cancellation and Additive Group Delays by Cascaded Fiber Bragg Gratings in Transmission Shamino Wang, Student Member, IEEE, Hernan Erlig, Student Member, IEEE, Harold R. Fetterman, Fellow, IEEE, Eli Yablonovitch, Fellow, IEEE, Victor Grubsky, Dmitry S. …
There the dispersion is, in fact, locally linear and light-like. The group velocity is, of course, not the speed of light but it is given by the degree of dispersion and the lattice constant. Such a situation is especially important when the linear dispersion is situated at the Fermi energy.
• The group velocity is the velocity of the wave with lower frequency, but the phase velocity is the velocity of the wave with higher frequency. Phase velocity The resulting wave may be a perturbation that acts over a short distance, i.e. a wave packet.
The fact that these two velocities are diﬁerent is a consequence of the fact that in a dispersive system, waves with diﬁerent frequencies move with diﬁerent speeds. The two velocities are the same in a non-dispersive system, which is why there was never any need to introduce the group …