APPARATUS FOR PROVIDING A PHASE SHIFT IN A PULSE AND METHOD OF USE THEREOF

摘要

The invention provides a method an apparatus for imparting phase shift in one or more pulses. The apparatus comprises at least one optical diffraction grating element; where each one of the grating elements comprises a grating having a constant line spacing (d) and a dielectric body in light coupling arrangement with the grating. The dielectric body has a side through which the pulse traverses. The side is at an angle alpha (alpha) with respect to the grating. Alpha alpha defines a path of the pulse in the dielectric body corresponding to an incident angle THETA i (theta incident) between the path and a plane normal to the grating. The incident angle theta i and grating line spacing (d) cooperate to provide negative second-order dispersion (SOD) and negative third-order dispersion (TOD) so as to compensate for any positive SOD and any positive TOD initially present in the pulse.