Patents by Inventor Constance J. Chang-Hasnain

Constance J. Chang-Hasnain 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).

  • Patent number: 11881683
    Abstract: A semiconductor device fabrication method in which a growing process is followed by a capping process in which a phosphor containing material cap layer is deposited over a final GaAs based layer. The wafer, containing many such substrates, can be removed from the reaction chamber to continue processing at a later time without creating an oxide layer on the final GaAs based layer. In continuing processing, a decomposition process selectively decomposes the phosphor containing material cap layer, after which a regrowing process is performed to grow additional layers of the device structure. The capping, decomposition and regrowth processes can be repeated multiple times on the semiconductor devices on the wafer during device fabrication.
    Type: Grant
    Filed: November 5, 2020
    Date of Patent: January 23, 2024
    Assignee: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Constance J. Chang-Hasnain, Jiaxing Wang, Jonas H. Kapraun, Emil Kolev
  • Publication number: 20210159668
    Abstract: A vertical cavity surface emitter device (e.g., VCSEL or RC-LED) containing a buried index-guiding current confinement aperture layer which is grown, and lithographically processed to define position, shape and dimension of an inner aperture. In a regrowth process, the aperture is filled with a single crystalline material from the third contact layer. The aperture provides for both current and optical confinement, while allowing for higher optical power output and improved thermal conductivity.
    Type: Application
    Filed: November 5, 2020
    Publication date: May 27, 2021
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Constance J. Chang-Hasnain, Jiaxing Wang, Kevin T. Cook, Jonas H. Kapraun, Emil Kolev
  • Publication number: 20210159669
    Abstract: A semiconductor device fabrication method in which a growing process is followed by a capping process in which a phosphor containing material cap layer is deposited over a final GaAs based layer. The wafer, containing many such substrates, can be removed from the reaction chamber to continue processing at a later time without creating an oxide layer on the final GaAs based layer. In continuing processing, a decomposition process selectively decomposes the phosphor containing material cap layer, after which a regrowing process is performed to grow additional layers of the device structure. The capping, decomposition and regrowth processes can be repeated multiple times on the semiconductor devices on the wafer during device fabrication.
    Type: Application
    Filed: November 5, 2020
    Publication date: May 27, 2021
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Constance J. Chang-Hasnain, Jiaxing Wang, Jonas H. Kapraun, Emil Kolev
  • Publication number: 20210135430
    Abstract: A widely tunable vertical-cavity surface-emitting laser (VCSEL) having a semiconductor cavity followed by an air-gap over which is a movable reflector. Lasing wavelength is controlled by a combination of the resonance of the semiconductor cavity, which is fixed, and the resonance of the air cavity, which can be changed by moving the reflector. Tuning range and slope of the VCSEL are increased by configuring the semiconductor cavity to be antiresonant at the center of the tuning range, which forces electromagnetic energy to be confined more strongly in the air gap than in the semiconductor, thus making emission wavelength more sensitive to the displacement of the tuning mirror.
    Type: Application
    Filed: November 5, 2020
    Publication date: May 6, 2021
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Constance J. Chang-Hasnain, Kevin T. Cook
  • Publication number: 20210135429
    Abstract: A high-contrast grating (HCG) structure and method of fabrication. The grating of the HCG is formed over a structural spacer layer, allowing a wider range of grating patterns, such as post and other forms which are lack structural support when fabricated over an air spacing beneath the grating elements. The technique involves etching the HCG grating, followed by oxidizing through this HCG grating into an oxide spacer layer beneath it creating a low-index area beneath the grating. This form of HCG reflector can be utilizes as upper and/or lower reflectors in fabricating vertical cavity surface emitting lasers (VCSELs).
    Type: Application
    Filed: November 5, 2020
    Publication date: May 6, 2021
    Applicant: THE REGENTS OF THE UNIVERSITY OF CALIFORNIA
    Inventors: Constance J. Chang-Hasnain, Kevin T. Cook, Jipeng Qi, Jiaxing Wang
  • Patent number: 6233263
    Abstract: A monitoring and control assembly for an optical system includes a tunable laser. The laser generates a divergent output beam along an optical axis. A first photodetector is provided. A wavelength selective filter is tilted at an angle relative to the optical axis that provides an angular dependence of a wavelength reflection of the wavelength selective filter and directs the reflected output beam towards the first photodetector.
    Type: Grant
    Filed: June 4, 1999
    Date of Patent: May 15, 2001
    Assignee: Bandwidth9
    Inventors: Constance J. Chang-Hasnain, Renato Dato, Peter Kner, Gabriel S. Li, Philip Worland, Rang-Chen Yu, Wupen Yuen
  • Patent number: 6174749
    Abstract: The present invention provides multiple-wavelength vertical-cavity surface-emitting laser (“MW-VCSEL”) arrays. These arrays are fabricated in a molecular beam epitaxy system or the like using two patterned-substrate growth techniques. The growth techniques can be used with an in-situ laser reflectometry. In one embodiment, a temperature dependent growth rate to create the devices is provided. In an alternative aspect, uniform growth is performed followed by a temperature-dependent desorption technique. These techniques provided desired wavelength span and desired characteristics.
    Type: Grant
    Filed: May 13, 1998
    Date of Patent: January 16, 2001
    Assignee: The Regents of the University of California
    Inventors: Wupen Yuen, Constance J. Chang-Hasnain, Gabriel S. Li
  • Patent number: 6148268
    Abstract: An efficient method for optimization of product characteristics or manufacturing processes. The method utilized a Chi-square model to identify error sources that contribute to the product or process variability. The method is particularly useful for evaluation of processes related to optics and electronics fabrication but also has application in fields where a chi-square distribution is observed.
    Type: Grant
    Filed: June 2, 1998
    Date of Patent: November 14, 2000
    Inventors: Yongan Wu, Constance J. Chang-Hasnain
  • Patent number: 5960024
    Abstract: A monolithic vertical optical cavity device built up along a vertical direction. The device has a bottom Distributed Bragg Reflector (DBR), a Quantum Well (QW) region consisting of least one active layer grown on top of the bottom DBR by using a Selective Area Epitaxy (SAE) mask such that the active layer or layers exhibit a variation in at least one physical parameter in a horizontal plane perpendicular to the vertical direction and a top DBR deposited on top of the QW region. A spacer is deposited with or without SAE adjacent the QW region. The device has a variable Fabry-Perot distance defined along the vertical direction between the bottom DBR and the top DBR and a variable physical parameter of the active layer. The varying physical parameter of the active layers is either their surface curvature and/or the band gap and both of these parameters are regulated by SAE. The monolithic vertical cavity device can be used as a Vertical Cavity Surface Emitting Laser (VCSEL) or a Vertical Cavity Detector (VCDET).
    Type: Grant
    Filed: March 30, 1998
    Date of Patent: September 28, 1999
    Assignee: Bandwidth Unlimited, Inc.
    Inventors: Gabriel S. Li, Wupen Yuen, Constance J. Chang-Hasnain
  • Patent number: 5771253
    Abstract: An electrostatically controlled cantilever apparatus for continuous tuning of the resonance wavelength of a Fabry-Perot cavity is disclosed. A resonant cavity is formed between two distributed Bragg reflector (DBR) mirrors each composed of multiple DBR layers. One such layer is replaced with a layer which has been fully oxidized except for a small aperture. This layer provides both optical and current confinement which allows for low threshold currents and high output power.
    Type: Grant
    Filed: January 29, 1997
    Date of Patent: June 23, 1998
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Constance J. Chang-Hasnain, Edward C. Vail, Marianne S. Wu
  • Patent number: 5760419
    Abstract: A compact and cost-effective wavelength meter and photodetector (10) that can measure simultaneously both wavelength and intensity has two back-to-back photodiodes (12 and 14) with a wavelength dependent distributed Bragg reflector (DBR) (28) positioned in-between. The wavelength resolution of this device is 1 nm or less. Easy design and fabrication of the device provides for reliable and cost-effective manufacturing. Applications include instrumentation and wavelength-division-multiplexing (WDM) in optical communication systems.
    Type: Grant
    Filed: July 31, 1996
    Date of Patent: June 2, 1998
    Assignees: The Board of Trustees of the Leland Stanford Junior University, The Regents of the University of California
    Inventors: Rashit F. Nabiev, Constance J. Chang-Hasnain, Lars E. Eng, Kam-Yin Lau
  • Patent number: 5629951
    Abstract: An electrostatically controlled cantilever apparatus for continuous tuning of the resonance wavelength of a Fabry-Perot cavity is disclosed. A resonant cavity is formed between two distributed Bragg reflector (DBR) mirrors. The top reflector is composed of a movable top DBR supported in a freely suspended cantilever, a variable-thickness air spacer layer and a fixed DBR. The bottom reflector is fixed on the substrate. By applying a tuning voltage to create electrostatic attraction, the cantilever may be deflected towards the substrate, thereby changing the thickness of the air spacer layer and consequently the resonant wavelength of the Fabry-Perot cavity.
    Type: Grant
    Filed: October 13, 1995
    Date of Patent: May 13, 1997
    Inventors: Constance J. Chang-Hasnain, Edward C. Vail, Marianne S. Wu
  • Patent number: 5627852
    Abstract: A semiconductor laser apparatus for broad-angle far-field addressing is disclosed. The apparatus comprises a laser block with lasing cavities. The lasing cavity mirrors are made by dry-etching of the semiconductor block. The width of a lasing cavity is defined by a p contact pad on the laser block; further lateral confinement of current to the cavity is achieved by proton implantation followed by etching of the proton layer. The apparatus achieves quasi-continuous beam steering with a total steering angle of 80.degree. and with 11 resolvable spots.
    Type: Grant
    Filed: August 16, 1995
    Date of Patent: May 6, 1997
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Yan Sun, Daniel A. Francis, Stephen A. Biellak, Constance J. Chang-Hasnain
  • Patent number: 5546209
    Abstract: Optical communication apparatus for simultaneously and reconfigurably establishing optical communication channels, comprises at least one light source and a plurality of wavelength-selective detectors optically associated with each light source, the detectors arranged one behind another. The apparatus uses wavelength-division-multiplexing (WDM) to facilitate simultaneous and reconfigurable communication of one-to-many 2-D optical planes. This advance dramatically increases the system functionality of optical-plane interconnects. Such a system is realized by incorporating several multiple wavelength vertical-cavity surface-emitting lasers (VCSEL) into each transmitting pixel and incorporating wavelength selectivity into each subsequent detecting plane which will absorb one wavelength and be transparent to the rest; these structures can be fabricated by slightly modifying existing technology.
    Type: Grant
    Filed: March 11, 1994
    Date of Patent: August 13, 1996
    Assignees: University of Southern California, Board of Trustees of the Leland Stanford University
    Inventors: Alan E. Willner, Constance J. Chang-Hasnain, James E. Leight
  • Patent number: 5541756
    Abstract: A network and method for routing optical signals through wavelength-coding of routing tags belonging to the optical signals. The routing tag preferably consists of one or more header pulses S.sub.i which are chosen from among header wavelengths .lambda..sub.hi. Preferably, the header wavelengths .lambda..sub.hi are different from wavelengths used by the data. The optical signal also has reset tag containing preferably one reset pulse R preferably having a unique reset wavelength .lambda..sub.r. The optical data is contained between the routing tag and the reset tag. The network has a splitter for dividing the optical signal into two or more split optical signals, which are copies of the original optical signal. A wavelength differentiating element is positioned in the path of one of the split optical signals to differentiate and preferably spatially resolve the header wavelengths of the header pulses.
    Type: Grant
    Filed: November 17, 1994
    Date of Patent: July 30, 1996
    Assignee: Board of Trustees of the Leland Stanford Junior Universty
    Inventors: Constance J. Chang-Hasnain, Kam-Yin Lau, Joseph W. Goodman, Anujan Varma
  • Patent number: 5539759
    Abstract: A single mode laser with a laser cavity consisting of an active medium and a first and second reflectors with an antiguide region or layer having a high refractive index positioned adjacent to the laser cavity to bleed off higher order lasing modes and preventing them from attaining the lasing condition. Specifically, light belonging to higher order modes leaks or bleeds into the antiguide region from the laser medium and from the first and second reflectors. When spacers for selecting the desired wavelength of laser light are provided, the light travelling through them leaks into the antiguide layer as well.Optimization of the bleeding of higher order modes into the passive antiguide region can be achieved by adjusting a taper angle of the laser cavity. Furthermore, by adjusting the ratio of the equivalent refractive index of the laser cavity and the passive antiguide region single mode operation at high current levels can be realized for apertures as large as 30 .mu.m.
    Type: Grant
    Filed: October 4, 1994
    Date of Patent: July 23, 1996
    Assignee: Board of Trustees of the Leland Stanford Junior University
    Inventors: Constance J. Chang-Hasnain, Yongan Wu, Rashit Nabiev
  • Patent number: 5029176
    Abstract: A one or two dimensional integrated array of multiple-wavelength, vertical-cavity lasers and its method of making. All lasers are simultaneously formed on a common substrate by the sequential vertical growth of a lower reflector, a lower spacer, an active light emitting region, an upper spacer and an upper reflector. Resonant cavities are formed between the upper and lower reflectors, the optical lengths of which determine the lasing wavelengths. According to the invention, during the growth of at least part of this vertical structure, the growth is made controllably non-uniform over the substrate, thereby providing a spatial variation over the substrate of the resonant cavity length. Such non-uniform deposition may be achieved by deposition from an off-normal source onto a stationary substrate, by thermal gradients in the substrate or by diffusion limited growth onto mesas or valleys of different widths.
    Type: Grant
    Filed: May 11, 1990
    Date of Patent: July 2, 1991
    Assignee: Bell Communications Research, Inc.
    Inventor: Constance J. Chang-Hasnain
  • Patent number: 4922500
    Abstract: A cross-coupled stripe laser array in which a substrate is formed with parallel grooves extending part way across the substrate and an area adjacent interior ends of the grooves is left planar. The orientations of the substrate and the grooves are chosen so as to produce differential epitaxial growth rates between the areas overlying the grooves and the area overlying the planar portion. A vertically confining optical structure is then deposited over both the grooved and planar portions. The structure includes a quantum well region, the bandgap of which depends upon its thickness. Electrical contacts are applied over the grooved regions. Thereby, the lasers overlying the grooves lase at a wavelength to which the equivalent structure overlying the planar portion is transparent, thus providing coupling between the stripe lasers.
    Type: Grant
    Filed: April 21, 1989
    Date of Patent: May 1, 1990
    Assignee: Bell Communications Research, Inc.
    Inventors: Constance J. Chang-Hasnain, Elyahou Kapon