Absorption grating with phase shift surface-emitting DFB laser structure or gain grating

摘要

It is a surface-emitting semiconductor laser having a semiconductor laser structure including a cladding layer and the active layer, opposed in close proximity to the active layer, an electrode and the substrate, current is injected into the semiconductor laser. In the laser structure, distribution gratings least second having elements which varies periodically, and the like. Each of the elements is either a low gain or high gain element element. The length of the low gain element and the length of the high gain element to form a grating period. The above-mentioned grating period, is within the range required to produce an optical signal in the optical telecommunications signal band. By phase shifting structure is provided in the grid central, and changes the mode profile of the output signal, the peak intensity occurs at the center of the cavity, in the meantime, the spatial hole burning arising from the mode profile is the change There is improved.