Patents by Inventor Abbas Behfar-Rad
Abbas Behfar-Rad has filed for patents to protect the following inventions. This listing includes patent applications that are pending as well as patents that have already been granted by the United States Patent and Trademark Office (USPTO).
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Patent number: 5594749Abstract: A planar, topology free, semiconductor quantum-well laser is described. The quantum-well active layer is formed and patterned in a specified region which is constrained on all sides by high bandgaps which are formed through the use of impurity-free diffusion techniques. After the impurity-free diffusion has taken place, an upper portion is then epitaxially deposited to complete the structure. High-power, single fundamental mode laser operation is achieved by funneling current into the constrained quantum-well active region, high bandgap regions in conjunction with low index of refraction in regions surrounding the active area. The structure is further designed to allow low beam divergence in the direction perpendicular to the semiconductor laser junction.Type: GrantFiled: August 19, 1994Date of Patent: January 14, 1997Assignee: International Business Machines CorporationInventors: Abbas Behfar-Rad, Christoph S. Harder, Heinz P. Meier
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Patent number: 5532608Abstract: An electrical probe card for parametric testing of microelectronics having reduced leakage current, includes a hydrophobic layer of a self curing silicone material coating the entire exposed surface of the ceramic card between exposed conductors. The hydrophobic layer has a thickness of less than 1 micrometer, preferably less than 0.1 micrometer and most preferably between 0.01 and 0.001 micrometers. The hydrophobic layer does not interfere with subsequent soldering to the contacts on the card, is inexpensive, solvent resistant and easily applied to new and pre-existing probe cards. The method of application involves applying an excess of the hydrophobic silicone material in its uncured state, followed by vigorously wiping excess material off to thin the layer, produce a good bond and clean the exposed conductors on the probe card.Type: GrantFiled: April 6, 1995Date of Patent: July 2, 1996Assignee: International Business Machines CorporationInventors: Abbas Behfar-Rad, Charles H. Perry, Krishna G. Sachdev
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Patent number: 5376582Abstract: A planar, topology free, semiconductor quantum-well laser is described. The quantum-well active layer is formed and patterned in a specified region which is constrained on all sides by high bandgaps which are formed through the use of impurity-free diffusion techniques. After the impurity-free diffusion has taken place, an upper portion is then epitaxially deposited to complete the structure. High-power, single fundamental mode laser operation is achieved by funneling current into the constrained quantum-well active region, high bandgap regions in conjunction with low index of refraction in regions surrounding the active area.The structure is further designed to allow low beam divergence in the direction perpendicular to the semiconductor laser junction.Type: GrantFiled: October 15, 1993Date of Patent: December 27, 1994Assignee: International Business Machines CorporationInventors: Abbas Behfar-Rad, Christoph S. Harder, Heinz P. Meier
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Patent number: 5311539Abstract: A semiconductor ridge waveguide laser structure with a roughened sidewall ridge that includes a substrate and an active layer disposed between lower and upper cladding layers. The structure further includes a waveguide ridge which comprises a contact layer and a trapezoidal ridge portion 16 of the upper cladding layer. The trapezoidal ridge portion has roughened sidewalls which provides low contact resistance.Type: GrantFiled: November 25, 1992Date of Patent: May 10, 1994Assignee: International Business Machines CorporationInventors: Abbas Behfar-Rad, Mark E. Jost, Christoph S. Harder
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Patent number: 5307357Abstract: What is disclosed is a semiconductor ridge waveguide laser structure having mechanical protection of ridge element by means of a thick, multi-layer organic material. The organic material, which may be a polyimide film, is deposited over the ridge element. The present invention also provides a fabrication process for depositing the protective means on the ridge element including deposition and photolithographic steps.Type: GrantFiled: November 5, 1992Date of Patent: April 26, 1994Assignee: International Business Machines CorporationInventors: Mark E. Jost, Ranee W. Kwong, Abbas Behfar-Rad, Peter P. Kwan
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Patent number: 5301202Abstract: A semiconductor ridge waveguide laser having a high value of horizontal far-field wherein the laser structure includes a substrate, a first or lower cladding layer composed of a AlGaAs on the substrate, an acting layer on the lower cladding layer, and a second or upper cladding layer composed of AlGaAs on the active layer. The upper cladding layer includes a raised ridge portion formed by etching the upper cladding layer through a mask. A contact layer is disposed on top of the ridge portion. The aluminum mole concentration of the lower cladding layer is greater than the aluminum mole concentration of the upper cladding layer. This forces the optical mode towards the upper cladding layer and results in an increased lateral waveguide confinement that produces a high horizontal far-field.Type: GrantFiled: February 25, 1993Date of Patent: April 5, 1994Assignee: International Business Machines, CorporationInventors: Christoph S. Harder, Sridhar V. Iyer, Heinz P. Meier, Alfred Phillips, Jr., Abbas Behfar-Rad
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Patent number: 5132983Abstract: Optical logic circuits utilize laser segments responsive to external optical signals to produce predetermined outputs in accordance with a desired logic function. Each segment has plural laser cavity legs joined at angled junctions to form at least part of a closed ring, with each segment including at least one light emitting, or exit, facet and at least one internally reflective facet at junctions of corresponding cavity legs. In a one-segment laser, the plural cavity legs form a closed ring. The laser is energized to propagate light in both directions around the ring, and external controls in the form of input light signals or reflective facets adjacent to a partially transmitting facet of the laser segment force unidirectional propagation to produce corresponding changes in the direction of emitted light from the laser. Multiple segments may be interconnected to produce more complex logic functions.Type: GrantFiled: March 28, 1991Date of Patent: July 21, 1992Assignee: Cornell Research Foundation, Inc.Inventor: Abbas Behfar-Rad
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Patent number: 5075743Abstract: A semiconductor structure for use in forming optical devices, such as lasers and LEDs, is disclosed. The structure includes a silicon base on which is formed by epitaxial growth, a crystalline material (such as AlGaP) structure or region that is nearly lattice matched to silicon. One or more quantum wells are formed in the crystalline material structure. A quantum well can be made of a direct bandgap material or an indirect bandgap material with isoelectronic centers (IECs). The regions on either side of the quantum wells can be graded to form a graded index separate confinement heterostructure (GRINSCH). To reduce problems of warpage, the crystalline material can be epitaxially grown in windows formed in a layer of silicon nitride or silicon dioxide on the silicon substrate. A multi-color array of optical devices can be provided with this structure.Type: GrantFiled: June 6, 1989Date of Patent: December 24, 1991Assignee: Cornell Research Foundation, Inc.Inventor: Abbas Behfar-Rad
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Patent number: 5031190Abstract: Optical logic circuits utilize laser segments responsive to external optical signals to produce predetermined outputs in accordance with a desired logic function. Each segment has plural laser cavity legs joined at angled junctions to form at least part of a closed ring, with each segment including at least one light emitting, or exit, facet and at least one internally reflective facet at junctions of corresponding cavity legs. In a one-segment laser, the plural cavity legs form a closed ring. The laser is energized to propagate light in both directions around the ring, and external controls in the form of input light signals or reflective facets adjacent to a partially transmitting facet of the laser segment force unidirectional propagation to produce corresponding changes in the direction of emitted light from the laser. Multiple segments may be interconnected to produce more complex logic functions.Type: GrantFiled: May 17, 1990Date of Patent: July 9, 1991Assignee: Cornell Research Foundation, Inc.Inventor: Abbas Behfar-Rad
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Patent number: 4924476Abstract: A triangular ring laser utilizing total internal reflection at two angled facets and a preselected amount of reflection at a third angled facet is disclosed. Partial transmission occurs through the third facet to reduce the threshold current required for achieving stimulated emission. The facets are at three corners of the triangular laser, and are formed by chemically assisted ion beam etching in which SiO.sub.2 is used as a mask, whereby smooth vertical walls are produced to form facets having reflective characteristics equivalent to those formed by cleaving.Type: GrantFiled: December 4, 1987Date of Patent: May 8, 1990Assignee: Cornell Research Foundation, Inc.Inventors: Abbas Behfar-Rad, S. Simon Wong
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Patent number: 4851368Abstract: A triangular ring laser utilizing total internal reflection at two angled facets and a preselected amount of reflection at a third angled facet is disclosed. Partial transmission occurs through the third facet to reduce the threshold current required for achieving stimulated emission. The facets are at three corners of the triangular laser, and are formed by chemically assisted ion beam etching in which SiO.sub.2 is used as a mask, whereby smooth vertical walls are produced to form facets having reflective characteristics equivalent to those formed by cleaving.Type: GrantFiled: December 4, 1987Date of Patent: July 25, 1989Assignee: Cornell Research Foundation, Inc.Inventors: Abbas Behfar-Rad, S. Simon Wong