Patents by Inventor Seng-Tiong Ho

Seng-Tiong Ho 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: 7643719
    Abstract: A superlens for controlling the size and the phase of an electromagnetic beam that passes through it, and a method for independently controlling the horizontal and vertical focusing of the electromagnetic beam using the superlens is provided. The superlens comprises a vertically GRIN multi-layer structure with one or more horizontally curved sidewalls. The vertical focusing is controlled by varying the longitudinal thickness of the multi-layer structure. The horizontal focusing is controlled by varying the profile and the radius of curvature of the horizontally curved sidewalls. Varying the thickness and radius of curvature is done by etching. Also provided is a method for making the superlens.
    Type: Grant
    Filed: March 10, 2004
    Date of Patent: January 5, 2010
    Assignee: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Patent number: 7623235
    Abstract: The present application discloses a system comprising a compact curved grating (CCG) and its associated compact curved grating spectrometer (CCGS) or compact curved grating wavelength multiplexer/demultiplexer (WMDM) module and a method for making the same. The system is capable of achieving a very small (resolution vs. size) RS factor. In the invention, the location of the entrance slit and detector can be adjusted in order to have the best performance for a particular design goal. The initial groove spacing is calculated using a prescribed formula dependent on operation wavelength. The location of the grooves is calculated based on two conditions. The first one being that the path-difference between adjacent grooves should be an integral multiple of the wavelength in the medium to achieve aberration-free grating focusing at the detector or output slit (or output waveguide) even with large beam diffraction angle from the entrance slit or input slit (or input waveguide).
    Type: Grant
    Filed: October 15, 2007
    Date of Patent: November 24, 2009
    Inventors: Seng-Tiong Ho, Seongsik Chang, Yingyan Huang
  • Patent number: 7616856
    Abstract: An optical medium has a graded effective refractive index with a high maximum refractive index change. The medium is formed using alternating layers of two or more materials having significantly different refractive indices. The thickness of the layers of at least one of the materials is substantially less than the effective light wavelength of interest. The effective index of refraction in a local region within the medium depends on the ratio of the average volumes of the two materials in the local region. A graded index of refraction is provided by varying the relative thicknesses of the two materials.
    Type: Grant
    Filed: August 7, 2008
    Date of Patent: November 10, 2009
    Assignee: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Publication number: 20090095882
    Abstract: An imaging device. In one embodiment, the imaging device includes a plurality of first electrode strips in parallel to each other along a first direction x, wherein each first electrode strip has an elongated body with a first surface and an opposite, second surface and a thickness n1. The imaging device also includes a plurality of second electrode strips in parallel to each other along a second direction y that is substantially perpendicular to the first direction x, wherein each second electrode strip has an elongated body with a first surface and an opposite, second surface and a thickness n2. The plurality of second electrode strips are positioned apart from the plurality of first electrode strips along a third direction z that is substantially perpendicular to the first direction x and the second direction y such that the plurality of first electrode strips and the plurality of second electrode strips are crossing each other accordingly to form a corresponding number of crossing points.
    Type: Application
    Filed: September 18, 2008
    Publication date: April 16, 2009
    Applicant: NORTHWESTERN UNIVERSITY
    Inventors: Boyang LIU, Seng-Tiong HO
  • Publication number: 20090046979
    Abstract: An optical medium has a graded effective refractive index with a high maximum refractive index change. The medium is formed using alternating layers of two or more materials having significantly different refractive indices. The thickness of the layers of at least one of the materials is substantially less than the effective light wavelength of interest. The effective index of refraction in a local region within the medium depends on the ratio of the average volumes of the two materials in the local region. A graded index of refraction is provided by varying the relative thicknesses of the two materials.
    Type: Application
    Filed: August 7, 2008
    Publication date: February 19, 2009
    Applicant: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Publication number: 20080285919
    Abstract: The present application discloses a system comprising a compact curved grating (CCG) and its associated compact curved grating spectrometer (CCGS) or compact curved grating wavelength multiplexer/demultiplexer (WMDM) module and a method for making the same. The system is capable of achieving a very small (resolution vs. size) RS factor. In the invention, the location of the entrance slit and detector can be adjusted in order to have the best performance for a particular design goal. The initial groove spacing is calculated using a prescribed formula dependent on operation wavelength. The location of the grooves is calculated based on two conditions. The first one being that the path-difference between adjacent grooves should be an integral multiple of the wavelength in the medium to achieve aberration-free grating focusing at the detector or output slit (or output waveguide) even with large beam diffraction angle from the entrance slit or input slit (or input waveguide).
    Type: Application
    Filed: October 15, 2007
    Publication date: November 20, 2008
    Inventors: Seng-Tiong Ho, Seongsik Chang, Yingyan Huang
  • Patent number: 7450309
    Abstract: An integrated signal manipulator for manipulating an optical signal. The optical signal manipulator is integrated on a single material substrate by etching a curved grating mirror. The curved grating mirror decomposes a first optical signal into focused spectral components. These focused spectral components are manipulated by signal-processing elements that are realized on the same material substrate. The manipulated spectral components are then combined by another curved grating mirror, on the same material substrate, to generate a second optical signal.
    Type: Grant
    Filed: June 13, 2006
    Date of Patent: November 11, 2008
    Assignee: Optonet, Inc.
    Inventors: Jing Ma, Seng-Tiong Ho
  • Patent number: 7426328
    Abstract: An optical medium has a graded effective refractive index with a high maximum refractive index change. The medium is formed using alternating layers of two or more materials having significantly different refractive indices. The thickness of the layers of at least one of the materials is substantially less than the effective light wavelength of interest. The effective index of refraction in a local region within the medium depends on the ratio of the average volumes of the two materials in the local region. A graded index of refraction is provided by varying the relative thicknesses of the two materials.
    Type: Grant
    Filed: August 28, 2003
    Date of Patent: September 16, 2008
    Assignee: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Publication number: 20080212914
    Abstract: New electro-optic (EO) phase modulator devices and geometries, as can be constructed using a transparent conductive component.
    Type: Application
    Filed: August 1, 2007
    Publication date: September 4, 2008
    Inventors: Tobin J. Marks, Seng-Tiong Ho, Jing Ma, Guoyang Xu
  • Patent number: 7303339
    Abstract: Optical modules and methods for making optical modules are described. In one embodiment, an optical module includes a substrate assembly including a photonic chip mounting region, and a groove extending towards the photonic chip mounting region. A waveguide is disposed within the groove. A plurality of spacers is on the chip mounting region, each spacer having a predetermined height. A photonic chip is placed on the plurality of spacers and above the chip mounting region, and an optical coupler is between the photonic chip and the waveguide.
    Type: Grant
    Filed: August 28, 2003
    Date of Patent: December 4, 2007
    Assignee: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Shide Cheng, Seng-Tiong Ho
  • Patent number: 7283233
    Abstract: The present invention discloses a system comprising a compact curved grating (CCG) and its associated compact curved grating spectrometer (CCGS) module and a method for making the same. The system is capable of achieving very small (resolution vs. size) RS factor. In the invention, the location of entrance slit and detector can be adjusted in order to have the best performance for a particular design goal. The initial groove spacing is calculated using a prescribed formula dependent on operation wavelength. The location of the grooves is calculated based on two conditions: the first one being that the path-difference between adjacent grooves should be an integral multiple of the wavelength in the medium and the second one being specific for a particular design goal of a curved-grating spectrometer. In an embodiment, elliptical mirrors each with focal points at the slit and detector are used for each groove to obtain aberration-free curved mirrors.
    Type: Grant
    Filed: March 20, 2004
    Date of Patent: October 16, 2007
    Inventors: Seng-Tiong Ho, Seongsik Chang
  • Publication number: 20070237442
    Abstract: New electro-optic (EO) phase modulator devices and geometries, as can be constructed using a transparent conductive component.
    Type: Application
    Filed: September 13, 2005
    Publication date: October 11, 2007
    Inventors: Tobin Marks, Seng-Tiong Ho, Jing Ma, Guoyang Xu
  • Patent number: 7218809
    Abstract: Composite optical waveguide structures or mode transformers and their methods of fabrication and integration are disclosed, wherein the structures or mode transformers are capable of bi-directional light beam transformation between a small mode size waveguide and a large mode size waveguide. One aspect of the present invention is directed to an optical mode transformer comprising a waveguide core having a high refractive index contrast between the waveguide core and the cladding, the optical mode transformer being configured such that the waveguide core has a taper wherein a thickness of the waveguide core tapers down to a critical thickness value, the critical thickness value being defined as a thickness value below which a significant portion of the energy of a light beam penetrates into the cladding layers surrounding the taper structure thereby enlarging the small mode size.
    Type: Grant
    Filed: August 31, 2005
    Date of Patent: May 15, 2007
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Publication number: 20060062521
    Abstract: Composite optical waveguide structures or mode transformers and their methods of fabrication and integration are disclosed, wherein the structures or mode transformers are capable of bidirectional light beam transformation between a small mode size waveguide and a large mode size waveguide. One aspect of the present invention is directed to an optical mode transformer comprising a waveguide core having a high refractive index contrast between the waveguide core and the cladding, the optical mode transformer being configured such that the waveguide core has a taper wherein a thickness of the waveguide core tapers down to a critical thickness value, the critical thickness value being defined as a thickness value below which a significant portion of the energy of a light beam penetrates into the cladding layers surrounding the taper structure thereby enlarging the small mode size.
    Type: Application
    Filed: August 31, 2005
    Publication date: March 23, 2006
    Applicant: Phosistor Technologies, Incorporated
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Patent number: 6888989
    Abstract: A coupling system for photonic integrated circuits and integrated optical waveguides is provided. A recess is formed in a substrate on which one or more integrated optical waveguides are disposed, the recess being located at the desired mounting location of the photonic integrated circuit. At least one end wall of the recess is inclined with respect to a normal to the substrate surface. At least one end face of a photonic integrated circuit is inclined to match the inclined end wall of the recess. The length, width, and depth of the recess are controlled so that inserting the photonic integrated circuit into the recess passively provides both lateral and vertical alignment of the photonic integrated circuit with the integrated optical waveguide(s).
    Type: Grant
    Filed: December 4, 2002
    Date of Patent: May 3, 2005
    Assignee: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Patent number: 6878562
    Abstract: A process for shifting the bandgap energy of a quantum well layer (e.g., a III-V semiconductor quantum well layer) without inducing complex crystal defects or generating significant free carriers. The process includes introducing ions (e.g., deep-level ion species) into a quantum well structure at an elevated temperature, for example, in the range of from about 200° C. to about 700° C. The quantum well structure that has had ions introduced therein includes an upper barrier layer, a lower barrier layer and a quantum well layer. The quantum well layer is disposed between the upper barrier layer and the lower barrier layer. The quantum well structure is then thermally annealed, thereby inducing quantum well intermixing (QWI) in the quantum well structure and shifting the bandgap energy of the quantum well layer. Also, a photonic device assembly that includes a plurality of operably coupled photonic devices monolithically integrated on a single substrate using the process described above.
    Type: Grant
    Filed: July 26, 2001
    Date of Patent: April 12, 2005
    Assignee: Phosistor Technologies, Incorporated
    Inventors: Boon-Siew Ooi, Seng-Tiong Ho
  • Patent number: 6879757
    Abstract: In a connection between an optical fiber or optical fiber array and an integrated optical waveguide or integrated optical waveguide array mounted or fabricated on a grooved substrate, an end face of an optical fiber array has a first facet and a second facet. The first facet has an inclination angle substantially equal to the inclination angle of an end wall of the substrate groove; the second facet has an inclination angle substantially equal to the inclination angle of the end face of the integrated optical waveguide. When the optical fiber array is mounted on the grooved substrate, each of the fibers rests in one of the substrate grooves. The first facet of each optical fiber end face is aligned with the end wall of the groove in which it rests, and the second facet is aligned with the end face of the integrated optical waveguide.
    Type: Grant
    Filed: December 4, 2002
    Date of Patent: April 12, 2005
    Assignee: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Shide Cheng, Seng-Tiong Ho
  • Publication number: 20050036738
    Abstract: An optical medium has a graded effective refractive index with a high maximum refractive index change. The medium is formed using alternating layers of two or more materials having significantly different refractive indices. The thickness of the layers of at least one of the materials is substantially less than the effective light wavelength of interest. The effective index of refraction in a local region within the medium depends on the ratio of the average volumes of the two materials in the local region. A graded index of refraction is provided by varying the relative thicknesses of the two materials.
    Type: Application
    Filed: August 28, 2003
    Publication date: February 17, 2005
    Inventors: Yan Zhou, Seng-Tiong Ho
  • Patent number: 6788838
    Abstract: A light transfer device is provided that includes a first light pathway having a first input and a first output and a second light pathway having a second output. The second light pathway is coupled to the first light pathway, and light from the first input is transferable between the first and second light pathways. An active medium is positioned along one of the first and second light pathways, and the active medium is capable of receiving optical energy that modifies the active medium so that the active medium controls the transfer of light between the first and second pathways.
    Type: Grant
    Filed: July 18, 2002
    Date of Patent: September 7, 2004
    Inventor: Seng-Tiong Ho
  • Publication number: 20040042729
    Abstract: Optical modules and methods for making optical modules are described. In one embodiment, an optical module includes a substrate assembly including a photonic chip mounting region, and a groove extending towards the photonic chip mounting region. A waveguide is disposed within the groove. A plurality of spacers is on the chip mounting region, each spacer having a predetermined height. A photonic chip is placed on the plurality of spacers and above the chip mounting region, and an optical coupler is between the photonic chip and the waveguide.
    Type: Application
    Filed: August 28, 2003
    Publication date: March 4, 2004
    Applicant: Phosistor Technologies, Inc.
    Inventors: Yan Zhou, Shide Cheng, Seng-Tiong Ho