DFB laser waveguide having periodic distribution of gains and absorptions of energy

Year	Description
1997	Invention patented by Yidong Huang on July 24th, 1997. Abstract: The waveguide of a distributed feedback laser is divided into first and second regions along a dividing line normal to the length of the waveguide. A phase shift is introduced to an interface between these regions so that the first region defines a gain-coupled diffraction grating structure when a first electric field is applied to it and the second region defines a loss-coupled diffraction grating structure when a second electric field opposite to the first electric field is applied. The former structure has a distribution of energy gains at periodic intervals and the latter structure has a distribution of energy absorptions at the same periodic intervals. One of the energy absorptions adjacent the dividing line is contiguous with one of the energy gains adjacent the dividing line. The energy gains and the energy absorptions occur at intervals equal to one-half wavelength of the output laser beam and the phase shift between the two regions is equal to a quarter wavelength of the laser beam.
Source: selected by the editor from original sources.

Invention: DFB laser waveguide having periodic distribution of gains and absorptions of energy