Patents by Inventor Sanjai Parthasarathi

Sanjai Parthasarathi 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).

  • Single channel four-port group delay compensation equalizer
    Patent number: 7457544
    Abstract: A group delay compensation equalizer is disclosed that employs a single channel four-port WDM device for compensating the group delay experienced by a plurality of wavelengths transmitted over different paths. The transmission differential between two wavelengths is compensated by transmitting the two wavelengths through two different paths where the fiber length in reflecting the second wavelength is equal to the transmission time difference between the two wavelengths. The single channel four-port group delay equalizer effectively provides a unidirectional signal flow, as compared to the conventional equalizer that transmits optical signals bi-directionally. The present invention reduces the cost of a group delay equalizer by simplifying the use of multiple three-port WDM devices into a single channel four-port WDM device.
    Type: Grant
    Filed: November 16, 2004
    Date of Patent: November 25, 2008
    Assignee: Avanex Corporation
    Inventors: John Feng, Xuehua Wu, Sanjai Parthasarathi, Giovanni Bararossa
  • Multilayer optical medium for near-field optical recording and reading
    Patent number: 6544716
    Abstract: An electro-optical storage system based on an optical head and a multilayer storage medium in a near-field configuration. The heat generated by absorption of a read/write beam adversely affects the interfacing between the optical head and the medium. The medium has a thermal insulation dielectric layer and/or a heat-dissipating layer to reduce thermal feedback from the medium to the optical head.
    Type: Grant
    Filed: June 19, 1998
    Date of Patent: April 8, 2003
    Assignee: Terastor Corporation
    Inventors: Roger Hajjar, Sanjai Parthasarathi, Lu Cheng
  • Measuring spacing between two surfaces via evanescent coupling
    Patent number: 6462349
    Abstract: A near-field optical system having a mechanism to determine a spacing between an optical surface and a reflective surface that are spaced by less one wavelength by using coupled radiation energy that has an evanescently-coupled portion.
    Type: Grant
    Filed: September 28, 1999
    Date of Patent: October 8, 2002
    Assignee: Terastor Corporation
    Inventors: Yung-Chieh Hsieh, Lily Zheng, Roger Hajjar, Sanjai Parthasarathi
  • Reduction of electrostatic charge build-up in storage medium
    Patent number: 6292459
    Abstract: A storage medium having a conducting path to dissipate electrostatic charge.
    Type: Grant
    Filed: May 14, 1999
    Date of Patent: September 18, 2001
    Assignee: Terastor Corporation
    Inventor: Sanjai Parthasarathi
  • Method and apparatus for measuring silver sheath thickness during drawing of high temperature superconducting wire
    Patent number: 5974885
    Abstract: An ultrasonic method to measure silver sheath thickness in silver sheathed, ceramic powder core High Temperature Superconductor (HTS) wires and an associated sensor system which is designed and developed for continuous, on-line, real-time measurement during wire drawing.
    Type: Grant
    Filed: May 7, 1997
    Date of Patent: November 2, 1999
    Assignee: Concurrent Technologies Corporation
    Inventors: Sanjai Parthasarathi, Michael D Aesoph, Jan Kajuch