Patents by Inventor Ashish Tandon

Ashish Tandon 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: 6730944
    Abstract: The invention provides a laser structure that operates at a wavelength of 1.3 &mgr;m and at elevated temperatures and a method of making same. The laser structure includes a quantum well layer of InAsP. The quantum well layer is sandwiched between a first barrier layer and a second barrier layer. Each barrier layer exhibits a higher bandgap energy than the quantum well layer. Also, each barrier layer comprises Gax(AlIn)1−xP in which x 0. This material has a higher bandgap energy than conventional barrier layer materials, such as InGaP. The resulting larger conduction band discontinuity leads to improved high temperature performance without increasing the threshold current of the laser structure.
    Type: Grant
    Filed: January 30, 2003
    Date of Patent: May 4, 2004
    Assignee: Agilent Technologies, Inc.
    Inventors: Ashish Tandon, Ying-Ian Chang, Scott W. Corzine, David P. Bour, Michael R. T. Tan
  • Patent number: 6711195
    Abstract: The long-wavelength photonic device comprises an active region that includes at least one quantum-well layer of a quantum-well layer material that comprises InyGa1-yAsSb in which y≧0, and that additionally includes a corresponding number of barrier layers each of a barrier layer material that includes gallium and phosphorus. The barrier layer material has a conduction-band energy level greater than the conduction-band energy level of the quantum-well layer material and has a valence-band energy level less than the valence-band energy level of the quantum-well layer material.
    Type: Grant
    Filed: February 28, 2002
    Date of Patent: March 23, 2004
    Assignee: Agilent Technologies, Inc.
    Inventors: Ying-Lan Chang, Scott W. Corzine, Russell D. Dupuis, Min Soo Noh, Jae Hyun Ryou, Michael R. T. Tan, Ashish Tandon
  • Publication number: 20040051113
    Abstract: The tunnel junction structure comprises a p-type tunnel junction layer of a first semiconductor material, an n-type tunnel junction layer of a second semiconductor material and a tunnel junction between the tunnel junction layers. At least one of the semiconductor materials includes gallium (Ga), arsenic (As) and either nitrogen (N) or antimony (Sb). The probability of tunneling is significantly increased, and the voltage drop across the tunnel junction is consequently decreased, by forming the tunnel junction structure of materials having a reduced difference between the valence band energy of the material of the p-type tunnel junction layer and the conduction band energy of the n-type tunnel junction layer.
    Type: Application
    Filed: September 12, 2002
    Publication date: March 18, 2004
    Inventors: Ying-Lan Chang, Ashish Tandon, Michael H. Leary, Michael R. T. Tan
  • Publication number: 20040001521
    Abstract: A semiconductor laser. The semiconductor laser has an indium-phosphide (InP) non-(100) substrate and an active region grown above the substrate. In so doing, embodiments of the present invention provide for the formation of a semiconductor laser with good morphology and low contamination while allowing the use of wide process windows. Opening the process window greatly simplifies the formation process, leads to more consistent results, and achieves better yields under mass production.
    Type: Application
    Filed: June 27, 2002
    Publication date: January 1, 2004
    Inventors: Ashish Tandon, Ying-Lan Chang, David Bour
  • Publication number: 20030211647
    Abstract: Several methods for producing an active region for a long wavelength light emitting device are disclosed. In one embodiment, the method comprises placing a substrate in an organometallic vapor phase epitaxy (OMVPE) reactor, the substrate for supporting growth of an indium gallium arsenide nitride (InGaAsN) film, supplying to the reactor a group-III-V precursor mixture comprising arsine, dimethylhydrazine, alkyl-gallium, alkyl-indium and a carrier gas, where the arsine and the dimethylhydrazine are the group-V precursor materials and where the percentage of dimethylhydrazine substantially exceeds the percentage of arsine, and pressurizing the reactor to a pressure at which a concentration of nitrogen commensurate with light emission at a wavelength longer than 1.2 um is extracted from the dimethylhydrazine and deposited on the substrate.
    Type: Application
    Filed: May 7, 2002
    Publication date: November 13, 2003
    Inventors: David P. Bour, Tetsuya Takeuchi, Ashish Tandon, Ying-Lan Chang, Michael R.T. Tan, Scott Corzine
  • Publication number: 20030161369
    Abstract: The long-wavelength photonic device comprises an active region that includes at least one quantum-well layer of a quantum-well layer material that comprises InyGa1-yAsSb in which y≧0, and that additionally includes a corresponding number of barrier layers each of a barrier layer material that includes gallium and phosphorus. The barrier layer material has a conduction-band energy level greater than the conduction-band energy level of the quantum-well layer material and has a valence-band energy level less than the valence-band energy level of the quantum-well layer material.
    Type: Application
    Filed: February 28, 2002
    Publication date: August 28, 2003
    Inventors: Ying-Lan Chang, Scott W. Corzine, Russell D. Dupuis, Min Soo Noh, Jae Hyun Ryou, Michael R.T. Tan, Ashish Tandon