Search Patents
  • System and method for measuring perturbations using a slow-light fiber Bragg grating sensor
    Patent number: 9025157
    Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.
    Type: Grant
    Filed: January 18, 2013
    Date of Patent: May 5, 2015
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: He Wen, Michel J. F. Digonnet, Shanhui Fan
  • System and method for measuring perturbations utilizing an optical filter and a narrowband optical source
    Patent number: 9347826
    Abstract: An optical device, a method of configuring an optical device, and a method of using a fiber Bragg grating is provided. The optical device includes a fiber Bragg grating, a narrowband optical source, and at least one optical detector. The fiber Bragg grating has a power transmission spectrum as a function of wavelength with one or more resonance peaks, each comprising a local maximum and two non-zero-slope regions with the local maximum therebetween. The light generated by the narrowband optical source has a wavelength at a non-zero-slope region of a resonance peak that is selected such that one or more of the following quantities, evaluated at the resonance peak, is at a maximum value: (a) the product of the group delay spectrum and the power transmission spectrum and (b) the product of the group delay spectrum and one minus the power reflection spectrum.
    Type: Grant
    Filed: April 3, 2015
    Date of Patent: May 24, 2016
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: He Wen, Michel J. F. Digonnet, Shanhui Fan
  • Ultrahigh-performance radiative cooler
    Patent number: 10508838
    Abstract: A radiative cooler is provided having a thermally insulated vacuum chamber housing that is configured to support a vacuum level of at least 10?5 Torr, an infared-transparent window that is sealably disposed on top of the thermally insulated vacuum chamber and is transparet in the range of 8-13 ?m, a selective emitter disposed inside the chamber, a mirror cone on the infared-transparent window, a selective emitter inside the chamber and is configured to passively dissipate heat from the earth into outer space through the infared-transparent window and is thermally decoupled from ambient air and solar irradiation but coupled to outer space, a heat exchanger with inlet and outlet pipes disposed below the selective emitter to cool water flowing through the pipe, a sun shade disposed vertically outside the chamber to minimize direct solar irradiation, and a mirror cone to minimize downward atmospheric radiation.
    Type: Grant
    Filed: July 17, 2017
    Date of Patent: December 17, 2019
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Zhen Chen, Linxiao Zhu, Aaswath Raman, Eli A. Goldstein, Shanhui Fan
  • High omnidirectional reflector
    Patent number: 6130780
    Abstract: A reflector, a method of producing same and a method of creating high omnidirectional reflection for a predetermined range of frequencies of incident electromagnetic energy for any angle of incidence and any polarization. The reflector includes a structure with a surface and a refractive index variation along the direction perpendicular to the surface while remaining nearly uniform along the surface. The structure is configured such that i) a range of frequencies exists defining a photonic band gap for electromagnetic energy incident along the perpendicular direction of said surface, ii) a range of frequencies exists defining a photonic band gap for electromagnetic energy incident along a direction approximately 90.degree. from the perpendicular direction of said surface, and iii) a range of frequencies exists which is common to both of said photonic band gaps. In an exemplary embodiment, the reflector is configured as a photonic crystal.
    Type: Grant
    Filed: February 19, 1999
    Date of Patent: October 10, 2000
    Assignee: Massachusetts Institute of Technology
    Inventors: John D. Joannopoulos, Shanhui Fan, Joshua N. Winn, Yoel Fink
  • Apparatuses and methods involving thermally tuned composite material
    Patent number: 11919574
    Abstract: An apparatus includes a substrate, at least one type of tuning material, and a composite material. The substrate has an interface surface or material that manifests, in response to light in a color spectrum, a particular color and a first thermal load. The particular color is associated with the first thermal load. The at least one type of tuning material manifests, in response to light in the color spectrum, the particular color and a second thermal load. The particular color is associated with the second thermal load. The first thermal load is different from the second thermal load. The composite material includes the interface surface or material and the at least one type of tuning material. The composite material manifests, in response to light in the color spectrum, the particular color and a tuned thermal load which is different than the first thermal load and the second thermal load.
    Type: Grant
    Filed: March 29, 2019
    Date of Patent: March 5, 2024
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Wei Li, Yu Shi, Shanhui Fan, Zhen Chen
  • Method for configuring air-core photonic-bandgap fibers free of surface modes
    Publication number: 20050118420
    Abstract: Coupling of core modes to surface modes in an air-core photonic-bandgap fiber (PBF) can cause large propagation losses. Computer simulations analyze the relationship between the geometry and the presence of surface modes in PBFs having a triangular hole pattern and identify ranges of core characteristic dimensions (e.g., radii) for which the fiber supports no surface modes (i.e., only core modes are present) over the entire wavelength range of the bandgap. In particular, for a hole spacing ? and a hole radius ?=0.47?, the core supports a single mode and supports no surface modes for core radii between about 0.7? and about 1.05?, which suggests that such fibers should exhibit a very low propagation loss. The existence of surface modes can be predicted simply and expediently by studying either the bulk modes alone or the geometry of the fiber without requiring a full analysis of the defect modes.
    Type: Application
    Filed: September 10, 2004
    Publication date: June 2, 2005
    Inventors: Hyang Kim, Shanhui Fan, Gordon Kino, Jonghwa Shin, Michel Digonnet
  • LASER-DRIVEN OPTICAL GYROSCOPE WITH PUSH-PULL MODULATION
    Publication number: 20150022818
    Abstract: A system and method for reducing coherent backscattering-induced errors in an optical gyroscope is provided. A first time-dependent phase modulation is applied to a first laser signal and a second phase modulation is applied to a second laser signal. The phase-modulated first laser signal propagates in a first direction through a waveguide coil and the phase-modulated second laser signal propagates in a second direction opposite the first direction through the waveguide coil. The first time-dependent phase modulation is applied to the phase-modulated second laser signal after the phase-modulated second laser signal propagates through the waveguide coil to produce a twice-phase-modulated second laser signal. The second time-dependent phase modulation is applied to the phase-modulated first laser signal after the phase-modulated first laser signal propagates through the waveguide coil to produce a twice-phase-modulated first laser signal.
    Type: Application
    Filed: June 6, 2013
    Publication date: January 22, 2015
    Inventors: Seth Lloyd, Michel J.F. Digonnet, Shanhui Fan
  • FIBER BRAGG GRATING DEVICES UTILIZING SLOW LIGHT
    Publication number: 20110001981
    Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device includes a fiber Bragg grating having a substantially periodic refractive index modulation along a length of the fiber Bragg grating. The fiber Bragg grating has a power transmission spectrum with a plurality of local transmission minima, wherein each pair of neighboring local transmission minima has a local transmission maximum therebetween. The local transmission maximum has a maximum power at a transmission peak wavelength. The optical device further includes a narrowband optical source in optical communication with a first optical path and a second optical path.
    Type: Application
    Filed: June 2, 2010
    Publication date: January 6, 2011
    Applicant: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J.F. Digonnet, Shanhui Fan, He Wen, Matthew A. Terrel
  • Light emitting device utilizing a periodic dielectric structure
    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
  • OPTICAL DEVICE UTILIZING FIBER BRAGG GRATING AND NARROWBAND LIGHT WITH NON-BRAGG WAVELENGTH
    Publication number: 20150330848
    Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device includes a fiber Bragg grating having a substantially periodic refractive index modulation along a length of the fiber Bragg grating. The fiber Bragg grating has a power transmission spectrum with a plurality of local transmission minima, wherein each pair of neighboring local transmission minima has a local transmission maximum therebetween. The local transmission maximum has a maximum power at a transmission peak wavelength. The optical device further includes a narrowband optical source in optical communication with a first optical path and a second optical path.
    Type: Application
    Filed: March 30, 2015
    Publication date: November 19, 2015
    Inventors: Michel J.F. Digonnet, Shanhui Fan, He Wen, Matthew A. Terrel
  • Photonic Blockchain Based on Optical Proof-of-Work
    Publication number: 20240004417
    Abstract: An apparatus for combined digital and optical processing of a cryptocurrency data block includes a digital processor that computes a hash vector from the cryptocurrency data block; a laser and splitter that produces optical input signals; optical modulators that binary phase-shift key modulate the optical input signals based on the hash vector; a photonic matrix multiplier circuit that performs an optically perform a discrete matrix-vector product operation on the modulated optical input signals to produce optical output signals, where the discrete matrix-vector product operation is defined by matrix elements limited to K discrete values, where 2?K?17; and photodetectors and comparators that perform optoelectronic conversions of the optical output signals to produce corresponding digital electronic output signals. The digital processor performs a second hash computation on an XOR result between the digital electronic output signals and the hash vector to produce a proof of work result.
    Type: Application
    Filed: March 25, 2023
    Publication date: January 4, 2024
    Inventors: Sunil K. Pai, David A.B. Miller, Olav Solgaard, Shanhui Fan, Michael Dubrovsky, Bogdan Penkovsky, Maynard Marshall Ball, JR.
  • UNIDIRECTIONAL CROW GYROSCOPE
    Publication number: 20090244544
    Abstract: An optical waveguide gyroscope includes at least one optical coupler configured to receive a first optical signal at a first port, to transmit a second optical signal to a second port, and to transmit a third optical signal to a third port. The optical waveguide gyroscope further includes a plurality of resonant waveguides optically coupled to the second port and the third port. The resonant waveguides are generally adjacent to one another and optically coupled to one another. At least a portion of the second optical signal propagates from the second port to the third port by propagating through the plurality of resonant waveguides, and at least a portion of the third optical signal propagates from the third port to the second port by propagating through the plurality of resonant waveguides.
    Type: Application
    Filed: April 1, 2009
    Publication date: October 1, 2009
    Applicant: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Matthew A. Terrel, Michel J.F. Digonnet, Shanhui Fan
  • Method for configuring air-core photonic-bandgap fibers free of surface modes
    Patent number: 7110650
    Abstract: Coupling of core modes to surface modes in an air-core photonic-bandgap fiber (PBF) can cause large propagation losses. Computer simulations analyze the relationship between the geometry and the presence of surface modes in PBFs having a triangular hole pattern and identify ranges of core characteristic dimensions (e.g., radii) for which the fiber supports no surface modes (i.e., only core modes are present) over the entire wavelength range of the bandgap. In particular, for a hole spacing ? and a hole radius ?=0.47?, the core supports a single mode and supports no surface modes for core radii between about 0.68? and about 1.05?. The existence of surface modes can be predicted simply and expediently by studying either the bulk modes alone or the geometry of the fiber without requiring a full analysis of the defect modes.
    Type: Grant
    Filed: September 10, 2004
    Date of Patent: September 19, 2006
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Hyang Kyun Kim, Shanhui Fan, Gordon S. Kino, Jonghwa Shin, Michel J. F. Digonnet
  • Photonic-bandgap fiber with a core ring
    Patent number: 7228041
    Abstract: A photonic-bandgap fiber includes a photonic crystal lattice with a first material having a first refractive index and a pattern of a second material formed therein. The second material has a second refractive index lower than the first refractive index. The photonic crystal lattice has a plurality of first regions that support intensity lobes of the highest frequency bulk mode and has a plurality of second regions that do not support intensity lobes of the highest frequency bulk mode. The photonic-bandgap fiber further includes a central core formed in the photonic crystal lattice. The photonic-bandgap fiber further includes a core ring having an outer perimeter. The core ring surrounds the central core, wherein the outer perimeter of the core ring passes only through the second regions of the photonic crystal lattice.
    Type: Grant
    Filed: May 6, 2005
    Date of Patent: June 5, 2007
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Hyang Kyun Kim, Shanhui Fan, Gordon S. Kino, Jonghwa Shin, Michel J. F. Digonnet, Vinayak Dangui
  • Effect of the Plasmonic Dispersion Relation on the Transmission Properties of Subwavelength Holes
    Publication number: 20070096087
    Abstract: Using a realistic plasmonic model, an optically thick electrically conductive film with subwavelength hole or holes therein is shown to always support propagating modes near the surface plasmon frequency, where cross-sectional dimensions of the hole or holes are less than about ?/2nh, ? being the wavelength of the light and nh the refractive index of the dielectric material in the hole or holes. This is the case even when material losses are taken into account. Based on the dispersion analysis, in both a single hole or hole array designs, propagating modes play a dominant role in the transport properties of incident light. These structures exhibit a new region of operation, while featuring a high packing density and diffraction-less behavior.
    Type: Application
    Filed: September 20, 2006
    Publication date: May 3, 2007
    Inventors: Peter Catrysse, Hocheol Shin, Shanhui Fan
  • Unidirectional crow gyroscope
    Patent number: 8068232
    Abstract: An optical waveguide gyroscope includes at least one optical coupler configured to receive a first optical signal at a first port, to transmit a second optical signal to a second port, and to transmit a third optical signal to a third port. The optical waveguide gyroscope further includes a plurality of resonant waveguides optically coupled to the second port and the third port. The resonant waveguides are generally adjacent to one another and optically coupled to one another. At least a portion of the second optical signal propagates from the second port to the third port by propagating through the plurality of resonant waveguides, and at least a portion of the third optical signal propagates from the third port to the second port by propagating through the plurality of resonant waveguides.
    Type: Grant
    Filed: April 1, 2009
    Date of Patent: November 29, 2011
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Matthew A. Terrel, Michel J. F. Digonnet, Shanhui Fan
  • Optical device utilizing fiber bragg grating and narrowband light with non-bragg wavelength
    Patent number: 9329089
    Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device includes a fiber Bragg grating having a substantially periodic refractive index modulation along a length of the fiber Bragg grating. The fiber Bragg grating has a power transmission spectrum with a plurality of local transmission minima, wherein each pair of neighboring local transmission minima has a local transmission maximum therebetween. The local transmission maximum has a maximum power at a transmission peak wavelength. The optical device further includes a narrowband optical source in optical communication with a first optical path and a second optical path.
    Type: Grant
    Filed: March 30, 2015
    Date of Patent: May 3, 2016
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J. F. Digonnet, Shanhui Fan, He Wen, Matthew A. Terrel
  • Optical device with fiber Bragg grating and narrowband optical source
    Patent number: 9019482
    Abstract: In certain embodiments, an optical device and a method of use is provided. The optical device includes a fiber Bragg grating having a substantially periodic refractive index modulation along a length of the fiber Bragg grating. The fiber Bragg grating has a power transmission spectrum with a plurality of local transmission minima, wherein each pair of neighboring local transmission minima has a local transmission maximum therebetween. The local transmission maximum has a maximum power at a transmission peak wavelength. The optical device further includes a narrowband optical source in optical communication with a first optical path and a second optical path.
    Type: Grant
    Filed: June 2, 2010
    Date of Patent: April 28, 2015
    Assignee: The Board of Trustees of the Leland Stanford Junior University
    Inventors: Michel J. F. Digonnet, Shanhui Fan, He Wen, Matthew A. Terrel
  • Ultra-slow down and storage of light pulses, and altering of pulse spectrum
    Publication number: 20060115212
    Abstract: Light pulses can be stopped and stored coherently, with an all-optical process that involves an adiabatic and reversible pulse bandwidth compression occurring entirely in the optical domain. Such a process overcomes the fundamental bandwidth-delay constraint in optics, and can generate arbitrarily small group velocities for light pulses with a given bandwidth, without the use of any coherent or resonant light-matter interactions. This is accomplished only by small refractive index modulations performed at moderate speeds and has applications ranging from quantum communications and computing to coherent all-optical memory devices. A complete time reversal and/or temporal/spectral compression and expansion operation on any electromagnetic field is accomplished using only small refractive index modulations and linear optical elements.
    Type: Application
    Filed: November 30, 2004
    Publication date: June 1, 2006
    Inventors: Mehmet Yanik, Shanhui Fan
  • High efficiency channel drop filter with absorption induced on/off switching and modulation
    Patent number: 6512866
    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: July 20, 2000
    Date of Patent: January 28, 2003
    Assignee: Massachusetts Institute of Technology
    Inventors: Shanhui Fan, Pierre R. Villeneuve, John D. Joannopoulos, Brent E. Little, Hermann A. Haus
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