Group Delay Dispersion (GDD)
The group delay dispersion is the change in the group delay depending on the frequency of the propagating light. Since a pulse will generally have a spread of wavelengths, differences in the group delay for the various wavelengths will cause the pulse to broaden in time. Typical units are [ps2] and is for a defined length of optical material.
Related Terms: Group Delay Dispersion (GDD), Group Index and Velocity, Group Velocity Delay (GVD), Second Order Dispersion