Patents by Inventor Shanhui Fan

Shanhui Fan 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: 6130969
    Abstract: A highly efficient channel drop filter. The filter employs a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes. The resonator-system includes one or more interacting resonant cavities which in addition to being coupled to the waveguides, can also be coupled directly among themselves and indirectly among themselves via the waveguides. Each component of the coupling element can be configured or adjusted individually. The geometry and/or dielectric constant/refractive index of the resonator-system are configured so that the frequencies and decay rates of the resonant modes are made to be substantially the same. The filter can achieve 100% signal transfer between the waveguides at certain frequencies, while completely prohibiting signal transfer at other frequencies. In exemplary embodiments, the filter is configured with photonic crystals.
    Type: Grant
    Filed: November 12, 1997
    Date of Patent: October 10, 2000
    Assignee: Massachusetts Institute of Technology
    Inventors: Pierre R. Villeneuve, Shanhui Fan, John D. Joannopoulos, Hermann A. Haus
  • Patent number: 6101300
    Abstract: A highly efficient channel drop filter. The filter employs a coupling element including a resonator-system between two waveguides, which contains at least two resonant modes. The resonator-system includes one or more interacting resonant cavities which in addition to being coupled to the waveguides, can also be coupled directly among themselves and indirectly among themselves via the waveguides. Each component of the coupling element can be configured or adjusted individually. The geometry and/or dielectric constant/refractive index of the resonator-system are configured so that the frequencies and decay rates of the resonant modes are made to be substantially the same. The filter can achieve 100% signal transfer between the waveguides at certain frequencies, while completely prohibiting signal transfer at other frequencies. In exemplary embodiments, the filter is configured with photonic crystals.
    Type: Grant
    Filed: May 15, 1998
    Date of Patent: August 8, 2000
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, Pierre R. Villeneuve, John D. Joannopoulos, Brent E. Little, Hermann A. Haus
  • Patent number: 6058127
    Abstract: A nonlinear dielectric material is incorporated within a photonic crystal as a means of changing the refractive index of a defect. In this way, the resonant frequency can be easily adjusted, after fabrication, by external mechanisms (either optical or electronic). The ability to tune the frequency of a resonant mode is useful for constructing photonic integrated devices, thus the invention enables the use of a photonic-crystal microcavity for such purposes. In one embodiment there is provided a photonic crystal having a periodic dielectric structure, and a defect positioned within the structure to define a microcavity. The defect includes a nonlinear material and being adapted to have an induced variation in index of refraction so as to tune the resonant mode of the microcavity.
    Type: Grant
    Filed: December 12, 1997
    Date of Patent: May 2, 2000
    Assignee: Massachusetts Institute of Technology
    Inventors: John D. Joannopoulos, Pierre R. Villeneuve, Shanhui Fan, Daniel S. Abrams
  • Patent number: 5990850
    Abstract: A metallodielectric photonic crystal including a plurality of elements, each having a non-dielectric component, arranged with respect to each other in a three-dimensionally periodic lattice. The non-dielectric components being spatially isolated from one another, the lattice exhibiting a band gap in the spectrum of electromagnetic radiation modes propagating through said lattice. A support structure positions the elements in the three-dimensionally periodic lattice. In an exemplary embodiment, the elements are metallic spheres arranged within dielectric material. The three-dimensionally periodic lattice can include a face-centered-cubic lattice which exhibits a unidirectional photonic band gap, or a diamond lattice which exhibits an omnidirectional photonic band gap. The diamond lattice structure includes a gap width to midgap frequency ratio which can exceed 60%.
    Type: Grant
    Filed: September 5, 1996
    Date of Patent: November 23, 1999
    Assignee: Massachusetts Institute of Technology
    Inventors: Elliott R. Brown, John D. Joannopoulos, Shanhui Fan, Pierre R. Villeneuve, Oliver B. McMahon
  • Patent number: 5955749
    Abstract: A light emitting device comprising a substrate and a dielectric structure having at least a two-dimensionally periodic variation of dielectric constant which exhibits a spectrum of electromagnetic modes including guided modes of frequencies below a predetermined frequency cutoff and radiation modes of frequencies above and below said predetermined frequency cutoff, the two-dimensionally periodic variation of dielectric constant of the dielectric structure introducing a band gap between the guided modes. A radiation source, such as a quantum well, is associated with said structure, and generates electromagnetic radiation which couples to the radiation modes resulting in radiation extraction from the structure. The band gap allows the radiation to couple to radiation modes rather than to guided modes resulting in radiation extraction from the structure. The structure can be fabricated such that a radiation reflector is disposed between the structure and the substrate.
    Type: Grant
    Filed: December 2, 1996
    Date of Patent: September 21, 1999
    Assignees: Massachusetts Institute of Technology, Trustees of Boston University
    Inventors: John D. Joannopoulos, Shanhui Fan, Pierre R. Villeneuve, E. Frederick Schubert
  • Patent number: 5682401
    Abstract: The present invention provides a resonant microcavity which includes a periodic dielectric waveguide, and a local defect in the periodic dielectric waveguide which accommodates spacial confinement of radiation generated within the waveguide around the defect. In an alternative embodiment, the present invention provides a method of enhancing radiation confinement within a resonant microcavity and minimizing radiation losses into an associated substrate, the microcavity configured within a periodic dielectric waveguide as a local defect which exhibits spacial radiation confinement, the method including the step of increasing the refractive index contrast between the microcavity and the substrate.
    Type: Grant
    Filed: June 18, 1996
    Date of Patent: October 28, 1997
    Assignee: Massachusetts Institute of Technology
    Inventors: John D. Joannopoulos, Shanhui Fan, Pierre R. Villeneuve, Robert D. Meade
  • Patent number: 5600483
    Abstract: A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, at least one layer having a stratum of a first material having a first dielectric constant and a plurality of parallel regions along a first axis lying in the plane of the layer, the regions including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.
    Type: Grant
    Filed: April 20, 1995
    Date of Patent: February 4, 1997
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, Pierre R. Villeneuve, John D. Joannopoulos, Robert D. Meade
  • Patent number: 5440421
    Abstract: A periodic dielectric structure and method of fabricating same, the structure having a three-dimensional photonic bandgap. The structure includes a plurality of layers, each layer having a stratum of a first material having a first dielectric constant and a plurality of parallel grooves along a first axis lying in the plane of the layer, the grooves including a second material having a second dielectric constant; and a plurality of parallel channels formed through the plurality of layers in a second axis orthogonal to the plane of the layers, the channels being adapted to comprise a third material having a third dielectric constant, thereby resulting in the structure having three-dimensional periodicity. In preferred embodiments, the second and third materials include air.
    Type: Grant
    Filed: May 10, 1994
    Date of Patent: August 8, 1995
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, Pierre R. Villeneuve, Robert D. Meade, John D. Joannopoulos