Patents by Inventor Anuradha M. Agarwal

Anuradha M. Agarwal 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: 10386237
    Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.
    Type: Grant
    Filed: May 22, 2018
    Date of Patent: August 20, 2019
    Assignee: Massachusetts Institute of Technology
    Inventors: Juejun Hu, Tian Gu, Hongtao Lin, Derek Matthew Kita, Anuradha M. Agarwal
  • Publication number: 20190234850
    Abstract: A photonic aerosol particle sensor includes a plurality of photonic waveguide resonators each having a photonic waveguide disposed along a separate waveguide resonator path and each photonic waveguide having a lateral waveguide width different than the waveguide width of other photonic waveguide resonators in the plurality. All waveguides in the plurality of photonic waveguide resonators have a common vertical thickness and are formed of a common photonic waveguide material. An optical input connection couples light into the waveguide resonators. A particle input conveys aerosol particles toward the waveguide resonators and an aerosol particle output conveys aerosol particles away from the waveguide resonators. At least one optical output connection is optically connected to accept light out of the plurality of photonic waveguide resonators to provide a signal indicative of at least one characteristic of the aerosol particles to be analyzed.
    Type: Application
    Filed: January 25, 2019
    Publication date: August 1, 2019
    Applicant: Massachusetts Institute of Technology
    Inventors: Robin Singh, Anuradha M. Agarwal, Danhao Ma, Peter X. Su, Brian W. Anthony
  • Publication number: 20180274981
    Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.
    Type: Application
    Filed: May 22, 2018
    Publication date: September 27, 2018
    Inventors: Juejun Hu, Tian Gu, Hongtao Lin, Derek Matthew Kita, Anuradha M. Agarwal
  • Patent number: 10006809
    Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.
    Type: Grant
    Filed: February 10, 2017
    Date of Patent: June 26, 2018
    Assignee: Massachusetts Institute of Technology
    Inventors: Juejun Hu, Tian Gu, Hongtao Lin, Derek Matthew Kita, Anuradha M. Agarwal
  • Publication number: 20170227399
    Abstract: A spectrometer includes an interferometer having a first interference arm and a second interference arm to produce interference patterns from incident light. At least one of the interference arms includes a series of cascaded optical switches connected by two (or more) waveguides of different lengths. Each optical switch directs the incident light into one waveguide or another, thereby changing the optical path length difference between the first interference arm and the second interference arm. This approach can be extended to multi-mode incident light by placing parallel interferometers together, each of which performs spectroscopy of one single mode in the multi-mode incident light. To maintain the compactness of the spectrometer, adjacent interferometers can share one interference arm.
    Type: Application
    Filed: February 10, 2017
    Publication date: August 10, 2017
    Inventors: Juejun Hu, Tian Gu, Hongtao Lin, Derek Matthew Kita, Anuradha M. Agarwal
  • Patent number: 9110221
    Abstract: In a photonic waveguide, there is provided an undercladding layer and a waveguide core, having a cross-sectional height and width, that is disposed on the undercladding layer. The waveguide core comprises a waveguide core material having a thermo-optic coefficient. A refractive index tuning cladding layer is disposed on top of the waveguide core. The refractive index tuning cladding layer comprises a refractive index tuning cladding material having an adjustable refractive index and an absorption length at a refractive index tuning radiation wavelength. A thermo-optic coefficient compensation cladding layer is disposed on top of the refractive index tuning cladding layer. The thermo-optic coefficient compensation cladding layer comprises a thermo-optic coefficient compensation material having a thermo-optic coefficient that is of opposite sign to the thermo-optic coefficient of the waveguide core material.
    Type: Grant
    Filed: February 8, 2013
    Date of Patent: August 18, 2015
    Assignee: Massachusetts Institute of Technology
    Inventors: Anuradha M. Agarwal, Antonio Canciamilla, Francesco Morichetti, Stefano Grillanda, Lionel C. Kimerling, Andrea Melloni, Jurgen Michel, Vivek Raghunathan, Vivek Singh
  • Publication number: 20130243383
    Abstract: In a photonic waveguide, there is provided an undercladding layer and a waveguide core, having a cross-sectional height and width, that is disposed on the undercladding layer. The waveguide core comprises a waveguide core material having a thermo-optic coefficient. A refractive index tuning cladding layer is disposed on top of the waveguide core. The refractive index tuning cladding layer comprises a refractive index tuning cladding material having an adjustable refractive index and an absorption length at a refractive index tuning radiation wavelength. A thermo-optic coefficient compensation cladding layer is disposed on top of the refractive index tuning cladding layer. The thermo-optic coefficient compensation cladding layer comprises a thermo-optic coefficient compensation material having a thermo-optic coefficient that is of opposite sign to the thermo-optic coefficient of the waveguide core material.
    Type: Application
    Filed: February 8, 2013
    Publication date: September 19, 2013
    Applicants: POLITECNICO DI MILANO, MASSACHUSETTS INSTITUTE OF TECHNOLOGY
    Inventors: Anuradha M. Agarwal, Antonio Canciamilla, Francesco Morichetti, Stefano Grillanda, Lionel C. Kimerling, Andrea Melloni, Jurgen Michel, Vivek Raghunathan, Vivek Singh
  • Patent number: 8394329
    Abstract: An agent sensing system may comprise an emitter optical resonator, a functionalized optical resonator, and a reference optical resonator. The emitter optical resonator may be configured to emit light at one or more system peak wavelengths. The functionalized optical resonator may be optically coupled to the emitter optical resonator and configured to propagate the emitted light in the absence of a particular agent, and filter the emitted light in the presence of the particular agent. The reference optical resonator may be optically coupled to at least one of the emitter optical resonator and the functionalized optical resonator such that an intensity of light propagated by the reference optical resonator is based at least on whether light emitted by the emitter optical resonator is filtered or propagated by the functionalized optical resonator.
    Type: Grant
    Filed: July 15, 2009
    Date of Patent: March 12, 2013
    Assignees: Raytheon Company, Massachusetts Institute of Technology
    Inventors: Frank B. Jaworski, Anuradha M. Agarwal
  • Publication number: 20120154810
    Abstract: An agent sensing system may comprise an emitter optical resonator, a functionalized optical resonator, and a reference optical resonator. The emitter optical resonator may be configured to emit light at one or more system peak wavelengths. The functionalized optical resonator may be optically coupled to the emitter optical resonator and configured to propagate the emitted light in the absence of a particular agent, and filter the emitted light in the presence of the particular agent. The reference optical resonator may be optically coupled to at least one of the emitter optical resonator and the functionalized optical resonator such that an intensity of light propagated by the reference optical resonator is based at least on whether light emitted by the emitter optical resonator is filtered or propagated by the functionalized optical resonator.
    Type: Application
    Filed: July 15, 2009
    Publication date: June 21, 2012
    Inventors: Frank B. Jaworski, Anuradha M. Agarwal
  • Patent number: 8203155
    Abstract: A multispectral pixel structure is provided that includes a plurality of stacked cavity arrangements for emitting or detecting a plurality of specified wavelengths, wherein each stacked cavity arrangement having a photoactive layer for spectral emission or detection of one of the specified wavelengths. The photoactive layer is positioned within a resonant cavity stack and the resonant cavity stack being positioned between two adjacent mirror stacks. A plurality of coupling-matching layers are positioned between one or more of the stack mirror arrangements for controlling optical phase and coupling strength between emitted or incident light and resonant modes in each of the stacked cavity arrangements.
    Type: Grant
    Filed: June 15, 2010
    Date of Patent: June 19, 2012
    Assignee: Massachusetts Institute of Technology
    Inventors: Jianfei Wang, Juejun Hu, Anuradha M. Agarwal, Xiaochen Sun, Lionel C. Kimerling
  • Publication number: 20110311180
    Abstract: An integrated optical waveguide includes a substrate, a waveguide under-cladding layer disposed on the substrate, and a waveguide core, having top and sidewall surfaces, disposed on the under-cladding layer. A glassy surface smoothing layer disposed on the waveguide core top surface and sidewall surfaces and has a refractive index, relative to a refractive index of the waveguide core, that enables guided optical transmission through the waveguide core and the glassy surface smoothing layer. In fabrication of the optical waveguide, a waveguide under-cladding layer is formed on a substrate and a waveguide core having sidewall surfaces and a top surface is formed on the under-cladding layer. A liquid suspension comprising particles of a glassy material is applied on the top and sidewall surfaces of the waveguide core. The applied liquid glassy particle suspension is heated to form a glassy surface smoothing layer on the waveguide core top surface and sidewall surfaces.
    Type: Application
    Filed: May 13, 2011
    Publication date: December 22, 2011
    Applicants: CLEMSON UNIVERSITY, MASSACHUSETTS INSTITUTE OF TECHNOLOGY
    Inventors: Juejun Hu, Nathan A. Carlie, Laeticia C. Petit, Anuradha M. Agarwal, Kathleen A. Richardson, Lionel C. Kimerling
  • Publication number: 20110127547
    Abstract: A multispectral pixel structure is provided that includes a plurality of stacked cavity arrangements for emitting or detecting a plurality of specified wavelengths, wherein each stacked cavity arrangement having a photoactive layer for spectral emission or detection of one of the specified wavelengths. The photoactive layer is positioned within a resonant cavity stack and the resonant cavity stack being positioned between two adjacent mirror stacks. A plurality of coupling-matching layers are positioned between one or more of the stack mirror arrangements for controlling optical phase and coupling strength between emitted or incident light and resonant modes in each of the stacked cavity arrangements.
    Type: Application
    Filed: June 15, 2010
    Publication date: June 2, 2011
    Inventors: Jianfei Wang, Juejun Hu, Anuradha M. Agarwal, Xiaochen Sun, Lionel C. Kimerling
  • Patent number: 7872233
    Abstract: A surface plasmon polariton (SPP) pixel structure is provided. The SPP pixel structure includes a coupling structure that couples the probing light into the SPP mode by matching the in-plane wave vector by changing the refractive index of the coupling structure using thermo-optic effects to vary the coupling strength of the probing light into the SPP mode. An absorber layer is positioned on the coupling structure for absorbing incident infrared/thermal radiation being detected.
    Type: Grant
    Filed: January 28, 2009
    Date of Patent: January 18, 2011
    Assignee: Massachusetts Institute of Technology
    Inventors: Juejun Hu, Ning-Ning Feng, Anuradha M. Agarwal, Lionel C. Kimerling
  • Publication number: 20100307579
    Abstract: A method of manufacturing a photovoltaic cell includes providing an active absorption layer, forming a pseudo-periodic grating adjacent to the active absorption layer, and forming a reflector adjacent to the pseudo-periodic grating. A photovoltaic cell includes an active absorption layer, a pseudo-periodic grating adjacent to the active absorption layer, and a reflector adjacent to the pseudo-periodic grating.
    Type: Application
    Filed: March 24, 2010
    Publication date: December 9, 2010
    Applicant: MASSACHUSETTS INSTITUTE OF TECHNOLOGY
    Inventors: Xing Sheng, Jifeng Liu, Jurgen Michel, Anuradha M. Agarwal, Lionel C. Kimerling
  • Patent number: 7831123
    Abstract: The invention provides a waveguide with a waveguide core having longitudinal sidewall surfaces, a longitudinal top surface, and a longitudinal bottom surface that is disposed on a substrate. An interface layer is disposed on at least one longitudinal sidewall surface of the waveguide core. A waveguide cladding layer is disposed on at least the waveguide core sidewall and top surfaces, over the interface layer. The waveguide of the invention can be produced by forming a waveguide undercladding layer on a substrate, and then forming a waveguide core on the undercladding layer. An interface layer is then formed on at least a longitudinal sidewall surface of the waveguide core, and an upper cladding layer is formed on a longitudinal top surface and on longitudinal sidewall surfaces of the waveguide core, over the interface layer.
    Type: Grant
    Filed: September 5, 2007
    Date of Patent: November 9, 2010
    Assignee: Massachusetts Institute of Technology
    Inventors: Daniel K. Sparacin, Anuradha M. Agarwal, Pradip K. Roy, Lionel C. Kimerling
  • Publication number: 20100187530
    Abstract: An infrared photodiode structure is provided. The infrared photodiode structure includes a doped semiconductor layer having ions of certain conductivity. An active photodetecting region is positioned on the doped semiconductor layer for detecting an infrared light signal. The active photodetecting region includes one or more amorphous semiconductor materials so as to allow for high signal-to-noise ratio being achieved by invoking carrier hopping and band conduction, under dark and illuminated conditions.
    Type: Application
    Filed: January 26, 2009
    Publication date: July 29, 2010
    Inventors: Juejun Hu, Ning-Ning Feng, Anuradha M. Agarwal, Lionel C. Kimerling
  • Publication number: 20100187419
    Abstract: A surface plasmon polariton (SPP) pixel structure is provided. The SPP pixel structure includes a coupling structure that couples the probing light into the SPP mode by matching the in-plane wave vector by changing the refractive index of the coupling structure using thermo-optic effects to vary the coupling strength of the probing light into the SPP mode. An absorber layer is positioned on the coupling structure for absorbing incident infrared/thermal radiation being detected.
    Type: Application
    Filed: January 28, 2009
    Publication date: July 29, 2010
    Inventors: Juejun Hu, Ning-Ning Feng, Anuradha M. Agarwal, Lionel C. Kimerling
  • Patent number: 7599584
    Abstract: A planar mid-infrared (mid-IR) integrated microphotonic platform includes at least one laser performing lasing functions. The at least one laser comprises chalcogenide glass. At least amplifier structure is coupled to the at least one laser for performing optical amplification. The at least amplifier structure comprises chalcogenide glass. At least one waveguide structure is coupled to the at least one amplifier structure for guiding an optical signal in the microphotonic platform. The at least waveguide structure comprises chalcogenide glass. At least one modulator structure is coupled to the at least one waveguide structure for modulating the optical signal. The at least modulator structure comprises chalcogenide glass. At least one photodetector is coupled to the at least one modulator structure for performing photodetecting functions of the microphotonic platform. The at least photodetector comprises chalcogenide glass.
    Type: Grant
    Filed: October 5, 2006
    Date of Patent: October 6, 2009
    Assignee: Massachusetts Institute of Technology
    Inventors: Juejun Hu, Anuradha M. Agarwal, Lionel C. Kimerling
  • Patent number: 7566942
    Abstract: A novel detection pixel micro-structure allowing the simultaneous and continuous detection of several discrete optical frequencies. A focal plane array comprises a plurality of multi-spectral detection pixels and a connecting platform to electrically connect the pixels. Each of the multi-spectral detection pixels form a resonant optical structure that comprises at least two periodic latticed dielectric reflectors, and at least one optical cavity between the said latticed dielectric reflectors. The latticed dielectric reflectors create a plurality of photonic bandgaps in the spectral response of the pixel. In addition, each optical cavity of the pixel comprises at least two optical resonant modes, corresponding to localized Bloch modes supported by the pixel dielectric structure, wherein each optical resonant mode is localized maximally at, and minimally away from, the optical cavity.
    Type: Grant
    Filed: October 17, 2005
    Date of Patent: July 28, 2009
    Assignee: Massachusetts Institute of Technology
    Inventors: Jean Francois Viens, Anuradha M. Agarwal, Lionel C. Kimerling
  • Patent number: 7447410
    Abstract: A ring resonator structure includes a semiconductor substrate, a core, and a cladding. Either the core or the cladding comprises chalcogenide glass to improve electromagnetic confinement in the ring resonator structure.
    Type: Grant
    Filed: July 14, 2006
    Date of Patent: November 4, 2008
    Assignee: Massachusetts Institute of Technology
    Inventors: Anuradha M. Agarwal, Juejun Hu, Lionel C. Kimerling