Heterostructure diode injection laser having a constricted active region
AssigneeInternational Business Machines Corporation
InventorsMartin B. Small, Peter S. Zory, Jr.
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Abstract
In a heterostructure diode injection laser, the active layer has a region of relatively lesser thickness in registration with a stripe geometry contact. Increased gain within the region of lesser thickness relative to adjacent regions of greater thickness tends to effectively confine lasing operation to the thinner or constricted region. The dimensions of the constricted active region may be readily selected to discriminate against multifilament lasing modes in order to produce a single spot laser beam over a wide range of injection levels.
Claims8
Heterostructure junction laser, comprising:
- a first active layer having an elongate constricted region;
- second and third confinement layers disposed on opposite sides of said first layer and in integral contact therewith,
- said second and third layers having a wider bandgap than said first layer;
- a p-n junction substantially parallel with said first layer and disposed so as to inject minority carriers into said first layer when forward biased;
- contact means for forward biasing said p-n junction over at least a part of said constricted region of said first layer;
- and
- first and second reflective faces at opposite ends of said elongate constricted region, said faces being parallel to one another and oriented perpendicular to the axial direction of said elongate constricted region;
- the dimensions of said constricted region being effective to constrain the laser to single filament operation when said p-n junction is forward biased.
Dependencies are inferred from the claim text.