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US 5,023,878 AGranted
Apparatus comprising a quantum well device and method of operating the apparatus
AssigneeAT&T Bell Laboratories
InventorsKurt Berthold, Anthony F. J. Levi
Life of this patent
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AssigneeAT&T Bell Laboratories
InventorsKurt Berthold, Anthony F. J. Levi
Estimating the term…
The inventive quantum well opto-electronic devices of cavity length L.sub.C comprise, in addition to a "gain" section, a "loss" section that is optically coupled to the gain section but electrically substantially isolated therefrom. Through change of the electrical bias on the loss section the modal gain of the cavity can be changed. Devices according to the invention are useful in a variety of applications. Exemplarily, by making (in an inventive laser) L.sub.C /L.sub.A greater than about 20 (L.sub.A is the length of the loss section) and making the electrical isolation between the gain section and the loss section greater than about 3 k.OMEGA., fast amplitude modulation of the laser radiation is possibly. By applying appropriate AR coatings to the cavity of an inventive device, a fast variable-gain optical amplifier can be made. Finally, an inventive laser can be switched electrically between two widely spaced wavelengths, the wavelength difference being at least 10 nm. This makes possible use of inventive devices in apparatus such as information storage systems, information processing systems, and communication systems. Methods of operating such apparatus are also disclosed.
Method of using apparatus comprising a laser that comprises a semiconductor body, the body comprising a gain section and, optically coupled to the gain section but electrically substantially isolated therefrom, a loss section, the apparatus further comprising means for causing the flow of an electrical current through the gain section, and still further comprising means for electrically biasing the loss section, the body comprising at least one quantum well, associated with the body being a length L.sub.C and a gain for radiation of a given wavelength, and associated with the quantum well being first and second energy sub-bands;
Apparatus comprising a laser that comprises a semiconductor body, the body comprising a gain section and, optically coupled to the gain section but electrically substantially isolated therefrom, a loss section, associated with the body being a length L.sub.C and a gain for radiation of a given wavelength, the body comprising at least one quantum well, associated with the quantum well being a first and a second energy sub-band;
Apparatus comprising a laser that comprises a semiconductor body, the body comprising a gain section and, optically coupled to the gain section but electrically substantially isolated therefrom, a loss section of length L.sub.A, the apparatus further comprising means for causing the flow of an electrical current through the gain section, and still further comprising means for electrically biasing the loss section, the body comprising at least one quantum well, associated with the body being a length L.sub.C and a gain for radiation of a given wavelength, and the apparatus further comprising means for utilizing radiation emitted by the laser;
Dependencies are inferred from the claim text.