Patents by Inventor John Joannopoulos

John Joannopoulos 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).

  • Publication number: 20050053321
    Abstract: A photonic crystal includes a plurality of photonic crystal slabs that is suited for confining TE polarizations and TM polarizations. The photonic crystal slabs include alternating slabs of dielectric rods and air holes. The alternating slabs create a lateral symmetry plane. The alternating slabs of dielectric rods and air holes further include planar line defects resulting in the formation of defect bands inside the bandgap of the photonic crystal.
    Type: Application
    Filed: May 20, 2004
    Publication date: March 10, 2005
    Inventors: Elefterios Lidorikis, Steven Johnson, Michelle Povinelli, John Joannopoulos
  • Publication number: 20050030613
    Abstract: A device for converting frequency of electromagnetic radiation includes a nonlinear medium that forms a moving grating in the nonlinear medium by introducing at opposite ends of the nonlinear medium a first set of electromagnetic radiation having varying frequencies. Electromagnetic radiation is inputted into the nonlinear medium at a first frequency and extracted at a second frequency from the nonlinear medium. The moving grating in the nonlinear medium allows for electromagnetic radiation to be converted into the second frequency.
    Type: Application
    Filed: April 8, 2004
    Publication date: February 10, 2005
    Inventors: Evan Reed, Marin Soljacic, John Joannopoulos, Steven Johnson, Maksim Skorobogatiy
  • Patent number: 6603911
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Grant
    Filed: August 1, 2002
    Date of Patent: August 5, 2003
    Assignee: Massachusetts Institute of Technology
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Publication number: 20020191929
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Application
    Filed: August 1, 2002
    Publication date: December 19, 2002
    Applicant: Massachusetts Institute of Technology, a Massachusetts corporation
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Patent number: 6463200
    Abstract: A device having at least one dielectric inner core region in which electromagnetic radiation is confined, and at least two dielectric outer regions surrounding the inner core region, each with a distinct refractive index. The outer regions confine electromagnetic radiation within the inner core region. The refractive indices, the number of outer regions, and thickness of the outer regions result in a reflectivity for a planar geometry that is greater than 95% for angles of incidence ranging from 0° to at least 80° for all polarizations for a range of wavelengths of the electromagnetic radiation. In exemplary embodiments, the inner core region is made of a low dielectric material, and the outer regions include alternating layers of low and high dielectric materials. In one aspect of the invention, the device is a waveguide, and in another aspect the device is a microcavity.
    Type: Grant
    Filed: October 14, 1999
    Date of Patent: October 8, 2002
    Assignee: Massachusetts Institute of Technology
    Inventors: Yoel Fink, Shanhui Fan, Edwin Thomas, Chiping Chen, John Joannopoulos
  • Patent number: 5999308
    Abstract: A method for introducing desired electromagnetic radiation into a photonic crystal having a photonic bandgap and at least one defect, wherein the desired electromagnetic radiation has a frequency within the photonic bandgap. The method includes the steps of: delivering source electromagnetic radiation having an electromagnetic frequency outside the photonic bandgap to the defect; and generating the desired electromagnetic radiation at the defect in response to the source electromagnetic radiation.
    Type: Grant
    Filed: April 1, 1998
    Date of Patent: December 7, 1999
    Assignee: Massachusetts Institute of Technology
    Inventors: Keith A. Nelson, John Joannopoulos
  • Patent number: 5526449
    Abstract: An optical circuit and a method for substantially eliminating radiation losses associated with optical integrated circuits and, in particular, bends in optical waveguides, is disclosed. The circuit and waveguide are fabricated on a substrate having a periodic dielectric structure. The periodic dielectric structure exhibits a range of frequencies of electromagnetic radiation which cannot propagate into the structure. The range of frequencies is known as a photonic band gap or frequency band gap. Radiation at a frequency within the frequency band gap of the structure is confined within the circuit and waveguide by the periodic dielectric structure surrounding the circuit and waveguide. Radiation losses are substantially eliminated.
    Type: Grant
    Filed: July 14, 1994
    Date of Patent: June 11, 1996
    Assignee: Massachusetts Institute of Technology
    Inventors: Robert Meade, John Joannopoulos, Oscar L. Alerhand
  • Patent number: 5471180
    Abstract: A dielectric resonator comprising a resonant defect structure diposed in a lattice structure formed of a plurality of multi-dimensional periodically arranged dielectric elements confines electromagnetic energy within a frequency band in the photonic band gap. The frequency band of the confined electromagnetic energy is tunable. The unique structure of the dielectric resonator leads to reduced power dissipation losses when used in microwave and millimeter wave components. Accordingly, the dielectric resonator may be used to produce high quality resonant cavities, filters and power generators.
    Type: Grant
    Filed: December 6, 1993
    Date of Patent: November 28, 1995
    Assignees: Lockheed Sanders, Inc., Massachusetts Institute of Technology
    Inventors: Karl Brommer, Henry Mullaney, Robert Meade, Andrew Rappe, John Joannopoulos
  • Patent number: 5389943
    Abstract: A filter utilizes a frequency selective, non-conductive, dielectric structure for filtering electromagnetic energy in the millimeter to far infrared frequency bands. The filter includes a non-conductive, high-dielectric, background material positioned to receive incident electromagnetic energy. A lattice structure comprised of a plurality of elongated elements formed of a non-conductive, high-dielectric material are disposed in a two-dimensional, periodic arrangement in the background material. The elements extend in parallel to one another through the background material for providing a range of frequencies over a band gap in which incident electromagnetic energy within the frequency range of the band gap is substantially prevented from propagating through the lattice structure. The dielectric structure can be adapted to operate as a band stop filter or a low pass filter.
    Type: Grant
    Filed: July 27, 1992
    Date of Patent: February 14, 1995
    Assignees: Lockheed Sanders, Inc., Massachusetts Institute of Technology
    Inventors: Karl Brommer, Henry Mullaney, Robert Meade, Andrew Rappe, John Joannopoulos