Abstract: Heterojunction devices having doping interface dipoles near the heterojunction interface are disclosed. The doping interface dipoles comprise two charge sheets of different conductivity type which are positioned within a carrier mean free path of the heterojunction interface.
Type:
Grant
Filed:
December 4, 1984
Date of Patent:
August 11, 1987
Assignee:
American Telephone and Telegraph Company, AT&T Bell Laboratories
Abstract: Apparatus is described which is especially well suited for simultaneous molecular beam epitaxy of materials, such as silicon, on a plurality of substrates.
Type:
Grant
Filed:
April 4, 1986
Date of Patent:
July 21, 1987
Assignee:
American Telephone and Telegraph Company AT&T Bell Laboratories
Abstract: Photoconductive gain is observed in a device comprising a superlattice having well and barrier layers, and cladding layers on the opposite sides of the superlattice with the barrier layers of the superlattice having an energy bandgap greater than the bandgap of the cladding layers.
Type:
Grant
Filed:
June 14, 1985
Date of Patent:
July 7, 1987
Assignee:
American Telephone and Telegraph Company, AT&T Bell Laboratories
Inventors:
Federico Capasso, Alfred Y. Cho, Albert L. Hutchinson, Khalid Mohammed
Abstract: An ordered-disordered transition is observed in semiconductor alloys which enables either the ordered or disordered structure to be produced.
Type:
Grant
Filed:
June 5, 1985
Date of Patent:
April 28, 1987
Assignee:
American Telephone and Telegraph Company, AT&T Bell Laboratories
Abstract: A semiconductor laser is frequency modulated and the output is put through an FM to IM converter. Intensity modulation is obtained at high frequency with the use of low switching current and minimal chirping oscillations.
Abstract: A double active layer semiconductor laser having single longitudinal mode operation is described. The laser comprises first and second active layers which are separated from each other by an intermediate barrier layer but are optically coupled to each other so that, effectively, single mode operation results.
Abstract: A ridge waveguide laser with the ridge being grown through a stripe opened in an oxide layer covering one of the cladding layers is described. In one embodiment, the cladding layer is corrugated and the ridge waveguide laser is a distributed feedback laser.
Abstract: Semiconductor lasers having cleaved optically coupled cavities operating electrically isolated produce output of a single longitudinal mode. Wavelength tuning of the single longitudinal mode is possible.
Abstract: Control circuits stabilize and maintain coupled-cavity lasers in a single longitudinal mode. The laser is electrically connected and mutually and optically coupled to a control means responsive to a light output signal from the laser for controlling the laser by generating a control signal to the laser to produce single longitudinal mode output. The single mode output is maintained even during high speed modulation in which the current or ambient conditions vary.
Abstract: A device using a birefringent optical fiber having periodic integral perturbations with the period equal to the birefringence beat length being useful as, for example, a polarization rotator and an optical filter.
Abstract: A large optical cavity injection laser having a plurality of active layers within the large optical cavity. The active layers having a thickness great enough so that quantum effects are not significant.
Abstract: A multi-quantum well laser having a Ga.sub.0.47 In.sub.0.53 As/Al.sub.0.48 In.sub.0.52 As active region emitting at 1.55 .mu.m and well layers having a thickness less than 150 Angstroms.
Type:
Grant
Filed:
July 11, 1983
Date of Patent:
July 8, 1986
Assignee:
AT&T Bell Laboratories
Inventors:
Kambiz Alavi, Alfred Y. Cho, Thomas P. Pearsall, Henryk Temkin
Abstract: A wavelength division multiplexing optical communications system and components thereof capable of using as many as 10.sup.4 channels are described. The system uses a waveguide resonator which is evanescently coupled to an optical fiber or waveguide. There is also an intracavity element optically coupled to the waveguide resonator and the control circuit element which is capable of tuning the frequency of either the intracavity element or the waveguide resonator, or both, to specific frequencies. There may be a plurality of devices optically coupled to each other through the system waveguide to form an optical communications system.
Abstract: Semiconductor devices having submonolayer superlattices are described. These devices may have periodic compositional variations in a direction parallel to the substrate surface as well as in the perpendicular direction. Such superlattices are useful in numerous types of devices including lasers, transistors, etc.
Abstract: A device having a selectively doped varying bandgap region with pyroelectric characteristics is described which is useful as a photodetector or temperature sensor. A plurality of selectively doped regions forming a superlattice may also be used. Ferroelectric devices are also described.
Type:
Grant
Filed:
July 31, 1984
Date of Patent:
May 20, 1986
Assignee:
AT&T Bell Laboratories
Inventors:
Federico Capasso, Arthur C. Gossard, Michael J. Stavola