Patents by Inventor Tirumala R. Ranganath

Tirumala R. Ranganath 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: 20150037902
    Abstract: A nanocalorimeter device includes a head that defines first dispensing regions configured to receive first drops of first liquids and a cover that defines second dispensing regions corresponding to the first dispensing regions and configured to receive second drops of second liquids. The first and second dispensing regions form corresponding nanocalorimeter cells when the cover is connected to the head, each nanocalorimeter cell thereby containing first and second drops which are combined during a measurement run into a merged drop. The nanocalorimeter device further includes mini-bars pre-dispensed in the second dispensing regions, respectively, each mini-bar including a high magnetic permeability material. A magnetic driver is configured to generate a rotating magnetic field around the nanocalorimeter cells, where the rotating magnetic field causes the mini-bars to spin, mixing the first and second liquids in the merged drop within each nanocalorimeter cell.
    Type: Application
    Filed: July 31, 2013
    Publication date: February 5, 2015
    Inventors: Tirumala R. Ranganath, Carol J. Courville, Richard Michael Kinder
  • Patent number: 7843977
    Abstract: A light source and the method for operating the same are disclosed. The light source includes first and second lasers, and first and second wavelength control assemblies. The lasers emit first and second light beams, respectively, at wavelengths that are determined by first and second wavelength control signals. First and second beam splitters split the first and second light beams, respectively, to create first and second sampling light beams. The first and second wavelength control assemblies receive sampling light beams and generate the first and second wavelength control signals such that the wavelengths of the first and second light beams differ by no more than a predetermined amount. The first and second wavelength control assemblies each include an absorption cell having a gas that has an optical absorption that varies with the wavelength of the first and second sampling light beams at wavelengths around the output wavelength of the light source.
    Type: Grant
    Filed: June 19, 2008
    Date of Patent: November 30, 2010
    Assignee: Agilent Technologies, Inc.
    Inventors: Eric Stephen Johnstone, Miao Zhu, Tirumala R. Ranganath
  • Patent number: 7747174
    Abstract: Multi-channel Fabry-Perot laser transmitters and methods of generating multiple modulated optical signals are described. In one aspect, an optical transmitter includes a Fabry-Perot (FP) laser, an optical isolator, an optical splitter, and multiple electroabsorption modulators (EAMs). The FP laser is operable to generate multimode laser light. The optical isolator is arranged to transmit the multimode laser light. The optical splitter has more than one optical output and an optical input that is arranged to receive the multimode laser light transmitted by the optical isolator. Each of the EAMs is operable to modulate a respective laser light output from a respective optical output of the optical splitter. In another aspect, multimode laser light is generated. The multimode laser light is directionally isolated. The directionally-isolated multimode laser light is divided into more than one divided laser light output.
    Type: Grant
    Filed: September 8, 2004
    Date of Patent: June 29, 2010
    Assignee: Avago Technologies Fiber IP (Singapore) Pte. Ltd.
    Inventor: Tirumala R. Ranganath
  • Patent number: 7734189
    Abstract: An optical transmitter includes a drive laser, a 1×N splitter, and an array of modulators. The 1×N splitter is coupled to split a beam from the drive laser into separated beams, and the modulators modulate the respective beam to represent respective data signals that are transmitted in parallel. Embodiments of the transmitter can provide high data rate communications at low cost by eliminating the need for an array of isolators and eliminating the need for high quality AR coatings. Additionally, an integrated optical circuit containing the modulator array does not require an array of lasers and can be fabricated at higher yields and lower costs.
    Type: Grant
    Filed: November 30, 2006
    Date of Patent: June 8, 2010
    Assignee: Avago Technologies Fiber IP (Singapore) Pte. Ltd.
    Inventor: Tirumala R. Ranganath
  • Publication number: 20090316740
    Abstract: A light source and the method for operating the same are disclosed. The light source includes first and second lasers, and first and second wavelength control assemblies. The lasers emit first and second light beams, respectively, at wavelengths that are determined by first and second wavelength control signals. First and second beam splitters split the first and second light beams, respectively, to create first and second sampling light beams. The first and second wavelength control assemblies receive sampling light beams and generate the first and second wavelength control signals such that the wavelengths of the first and second light beams differ by no more than a predetermined amount. The first and second wavelength control assemblies each include an absorption cell having a gas that has an optical absorption that varies with the wavelength of the first and second sampling light beams at wavelengths around the output wavelength of the light source.
    Type: Application
    Filed: June 19, 2008
    Publication date: December 24, 2009
    Inventors: Miao Zhu, Erick Stephen Johnstone, Tirumala R. Ranganath
  • Patent number: 7502567
    Abstract: Electroabsorption-modulated Fabry-Perot lasers and methods of making the same are described. In one aspect, a light source includes a Fabry-Perot (FP) laser that is operable to generate multimode laser light, an electroabsorption modulator (EAM) that is configured to selectively absorb and transmit laser light traveling therethrough, and an optical isolator. The optical isolator is on an optical path between the FP laser and the EAM. The optical isolator is configured to transmit laser light traveling along the optical path from the FP laser to the EAM.
    Type: Grant
    Filed: June 15, 2004
    Date of Patent: March 10, 2009
    Assignee: Avago Technologies Fiber IP (Singapore) Pte. Ltd.
    Inventor: Tirumala R. Ranganath
  • Patent number: 7425726
    Abstract: Electro-absorption modulators and methods of making the same are described. In one aspect, an electroabsorption modulator includes first and second electrodes, first and second cladding regions, an active region, and a tunnel junction structure. The first and second cladding regions are between the first and second electrodes. The active region is between the first and second cladding regions and includes a light absorption region. The tunnel junction structure is between the active region and one of the first and second cladding regions.
    Type: Grant
    Filed: May 19, 2004
    Date of Patent: September 16, 2008
    Assignee: Avago Technologies Fiber IP Pte Ltd.
    Inventor: Tirumala R. Ranganath
  • Publication number: 20080159347
    Abstract: Undoped layers are introduced in the passive waveguide section of a butt-joined passive waveguide connected to an active structure. This reduces the parasitic capacitance of the structure.
    Type: Application
    Filed: March 11, 2008
    Publication date: July 3, 2008
    Applicant: AVAGO TECHNOLOGIES FIBER IP (SINGAPORE) PTE. LTD.
    Inventors: Tirumala R. Ranganath, Jintian Zhu
  • Publication number: 20080131141
    Abstract: An optical transmitter includes a drive laser, a 1×N splitter, and an array of modulators. The 1×N splitter is coupled to split a beam from the drive laser into separated beams, and the modulators modulate the respective beam to represent respective data signals that are transmitted in parallel. Embodiments of the transmitter can provide high data rate communications at low cost by eliminating the need for an array of isolators and eliminating the need for high quality AR coatings. Additionally, an integrated optical circuit containing the modulator array does not require an array of lasers and can be fabricated at higher yields and lower costs.
    Type: Application
    Filed: November 30, 2006
    Publication date: June 5, 2008
    Inventor: Tirumala R. Ranganath
  • Patent number: 7368062
    Abstract: Undoped layers are introduced in the passive waveguide section of a butt-joined passive waveguide connected to an active structure. This reduces the parasitic capacitance of the structure.
    Type: Grant
    Filed: September 17, 2004
    Date of Patent: May 6, 2008
    Assignee: Avago Technologies Fiber IP Pte Ltd
    Inventors: Tirumala R. Ranganath, Jintian Zhu
  • Patent number: 7098471
    Abstract: Semiconductor quantum well devices and methods of making the same are described. In one aspect, a device includes a quantum well structure that includes semiconductor layers defining interleaved heavy-hole and light-hole valance band quantum wells. Each of the quantum wells includes a quantum well layer interposed between barrier layers. One of the semiconductor layers that functions as a barrier layer of one of the light-hole quantum wells also functions as the quantum well layer of one of the heavy-hole quantum wells. Another of the semiconductor layers that functions as a barrier layer of one of the heavy-hole quantum wells also functions as the quantum well layer of one of the light-hole quantum wells.
    Type: Grant
    Filed: June 14, 2004
    Date of Patent: August 29, 2006
    Assignee: Avago Technologies Fiber IP (Singapore) Pte. Ltd.
    Inventors: Tirumala R. Ranganath, Jintian Zhu
  • Patent number: 6744953
    Abstract: Planar optical waveguide apparatus and methods for fabricating planar optical waveguide apparatus. The apparatus has a core layer and a cladding layer, the core layer having at least one optical waveguide, and an alignment structure spaced from and positioned with respect to the at least one optical waveguide to facilitate measuring a position of the at least one optical waveguide. The alignment structure has a first alignment structure, such as a reflecting member, to facilitate measuring a height of the at least one optical waveguide; and a second alignment structure, such as alignment marks, to facilitate measuring positions of the at least one optical waveguide in a plane of the at least one optical waveguide. The method includes forming both the optical waveguide and at least a portion of the alignment structure simultaneously in a single processing step to ensure that the optical waveguide and the alignment structure are in perfect registration.
    Type: Grant
    Filed: September 7, 2001
    Date of Patent: June 1, 2004
    Assignee: Agilent Technologies, Inc.
    Inventors: Brian Elliot Lemoff, William Gong, Richatd P. Tella, Tirumala R. Ranganath
  • Publication number: 20030048994
    Abstract: Planar optical waveguide apparatus and methods for fabricating planar optical waveguide apparatus. The apparatus has a core layer and a cladding layer, the core layer having at least one optical waveguide, and an alignment structure spaced from and positioned with respect to the at least one optical waveguide to facilitate measuring a position of the at least one optical waveguide. The alignment structure has a first alignment structure, such as a reflecting member, to facilitate measuring a height of the at least one optical waveguide; and a second alignment structure, such as alignment marks, to facilitate measuring positions of the at least one optical waveguide in a plane of the at least one optical waveguide. The method includes forming both the optical waveguide and at least a portion of the alignment structure simultaneously in a single processing step to ensure that the optical waveguide and the alignment structure are in perfect registration.
    Type: Application
    Filed: September 7, 2001
    Publication date: March 13, 2003
    Inventors: Brian Elliot Lemoff, William Gong, Richard P. Tella, Tirumala R. Ranganath
  • Publication number: 20020161289
    Abstract: A composite detector device that incorporates a plurality of types of detector elements to cover a broad wavelength range. There may be one or more individual detector elements of each detector type. The individual detector elements are positioned upon a single substrate so that when light from a sample passes through a spectral dispersing element, each detector element is exposed to light of a predetermined, limited wavelength range.
    Type: Application
    Filed: April 30, 2001
    Publication date: October 31, 2002
    Inventors: George W. Hopkins, Ganapati R. Mauze, Tirumala R. Ranganath
  • Patent number: 5119450
    Abstract: An optical circuit element for processing single mode light. The element is of the type that includes input and output waveguides that communicate with an intermediate waveguide network. The input and output waveguides are designed to support only the fundamental mode of light throughout a predetermined optical wavelength range while the waveguides of the intermediate waveguide network can support higher order modes. By maintaining adiabatic optical path transitions throughout the element, cross-coupling between the fundamental and higher order modes is avoided so that broad wavelength range single mode signal processing is achieved.
    Type: Grant
    Filed: August 20, 1991
    Date of Patent: June 2, 1992
    Assignee: Hewlett-Packard Company
    Inventors: Tirumala R. Ranganath, David W. Dolfi
  • Patent number: 4942583
    Abstract: A grating tuned laser system having an anamorphic optical section (72) that produces a line image on the grating (73). This system is insensitive to tilt of the grating (73) about an axis (T) perpendicular to the rulings (74) of the grating (73). An embodiment that utilizes a degenerate external cavity is also insensitive to small lateral misalignment of the optical elements.
    Type: Grant
    Filed: June 17, 1988
    Date of Patent: July 17, 1990
    Assignee: Hewlett-Packard Company
    Inventors: Moshe Nazarathy, Paul Zorabedian, William Richard, Tirumala R. Ranganath
  • Patent number: 4706103
    Abstract: A pair of rectifying electrodes (20) are formed on the surface (23) of a semiconductor waveguide device (10) around the waveguide region (18). Rectifying Schottky contacts (22) or p-n junctions (24) can be utilized. A bipolar voltage signal (30) is applied across the rectifying electrodes (20), reducing the voltage and power requirements and producing a bipolar electric field transversely across the waveguide (18). The electrode scheme (20) also provides low microwave loss.
    Type: Grant
    Filed: June 17, 1985
    Date of Patent: November 10, 1987
    Assignee: Hughes Aircraft Company
    Inventor: Tirumala R. Ranganath