Apparatus comprising a quantum well device and method of operating the apparatus
First Claim
1. 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 LC and a gain for radiation of a given wavelength, and associated with the quantum well being first and second energy sub-bands;
- and the apparatus further comprising means for utilizing radiation emitted by the laser;
wherein the method comprises(a) causing the flow of an electrical current through the gain section;
(b) electrically biasing the loss section, the electrical bias selected such that the laser emits first radiation of wavelength λ
1 ;
characterized in that the apparatus also comprises means for changing the bias conditions on the loss section, and the method further comprises(c) changing the bias conditions on the loss section without changing LC, such that the laser emits second radiation of wavelength λ
2 different from λ
1, with |λ
1 -λ
2 | being at least 10 nm.
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Abstract
The inventive quantum well opto-electronic devices of cavity length LC 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) LC /LA greater than about 20 (LA is the length of the loss section) and making the electrical isolation between the gain section and the loss section greater than about 3 kΩ, 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.
20 Citations
13 Claims
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1. 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 LC and a gain for radiation of a given wavelength, and associated with the quantum well being first and second energy sub-bands;
- and the apparatus further comprising means for utilizing radiation emitted by the laser;
wherein the method comprises(a) causing the flow of an electrical current through the gain section; (b) electrically biasing the loss section, the electrical bias selected such that the laser emits first radiation of wavelength λ
1 ;characterized in that the apparatus also comprises means for changing the bias conditions on the loss section, and the method further comprises (c) changing the bias conditions on the loss section without changing LC, such that the laser emits second radiation of wavelength λ
2 different from λ
1, with |λ
1 -λ
2 | being at least 10 nm. - View Dependent Claims (2, 3, 4, 5, 6, 7, 8, 9, 10)
- and the apparatus further comprising means for utilizing radiation emitted by the laser;
-
11. 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 LC 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;
- the apparatus further comprising
(a) means for causing the flow of an electrical current through the gain section; (b) means for changing the bias conditions on the loss section, the means comprising means for applying an electrical bias to the loss section; and (c) means for utilizing radiation emitted by the laser;
characterized in that(d) the means of (b) permit changing, without changing LC, the bias conditions on loss section from a first value associated with the emission of first radiation of wavelength λ
1 to a second value that is associated with the emission of second radiation of wavelength λ
2, with |λ
1 -λ
2 | being at least 10 nm. - View Dependent Claims (12)
- the apparatus further comprising
-
13. 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 LA, 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 LC and a gain for radiation of a given wavelength, and the apparatus further comprising means for utilizing radiation emitted by the laser;
- characterized in that
(a) LC /LA is greater than 20; and (b) an electrical isolation resistance between the gain section and the loss section is at least about 3 kΩ
;
whereby the gain for radiation of the given wavelength can be changed by changing the loss section bias, and whereby fast modulation of radiation emitted by the laser can be attained.
- characterized in that
Specification