Patents by Inventor Sthitadhi Das

Sthitadhi Das 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: 7310974
    Abstract: A method for drawing an optical fiber having reduced polarization mode dispersion (PMD) draws an optical fiber from an optical fiber preform whose core ovality is at max about 3%, coats the optical fiber with acrylic polymer and twists the coated optical fiber with a pair of spinning wheels. The twisting of the fiber is achieved by four discrete spin rates that repeat in a periodic fashion after the drawing of certain lengths of the optical fiber. At least one of the spin rates varies in a trapezoidal manner along the respective one of drawn lengths of the optical fiber.
    Type: Grant
    Filed: January 9, 2004
    Date of Patent: December 25, 2007
    Assignee: Sterlite Optical Technologies Limited
    Inventors: Sangeeta Mohanty, Nacham Sridhar, Salaj Sinha, Nitesh Gulati, Sthitadhi Das
  • Patent number: 7209620
    Abstract: A dispersion optimized fiber having higher spot area comprising a center core region, a cladding region, a ring core region and an outer glass region is provided, wherein the cladding is provided onto the outer periphery of the center core, and the ring core is provided onto the outer periphery of the cladding, and the outer glass region surrounds the ring core region, and the center core and the ring core have refractive indices higher than the outer glass region and the cladding region has lower refractive index than the outer glass region, and the refractive indices are constrained by the equation n1>n3>n4>n2.
    Type: Grant
    Filed: January 22, 2004
    Date of Patent: April 24, 2007
    Assignee: Sterlite Optical Technologies Limited
    Inventors: Shashikant Prasad, Sthitadhi Das, Nageswaran Senthil Kumar, Sanjeet Bhatia, Salaj Sinha, Pankaj Khanna
  • Patent number: 6879764
    Abstract: Dispersion shifted fiber having low dispersion slope comprising a center core, two claddings, a ring core and the outer glass region, wherein the first cladding is provided onto the outer periphery of the center core, the second cladding is provided onto outer periphery of the first cladding and the ring core is provided onto outer periphery of the second cladding, and the outer glass region surrounds the ring core, and the center core and the ring core have higher refractive indices, and the claddings have lower refractive indices than the outer glass region, and the refractive indices are constrained by the equation n1>n4>n5>n2>n3.
    Type: Grant
    Filed: April 26, 2002
    Date of Patent: April 12, 2005
    Assignee: Sterlite Optical Technologies Limited
    Inventors: Samaresh Changdar, Sthitadhi Das
  • Publication number: 20050058418
    Abstract: A dispersion optimized fiber having higher spot area comprising a center core region, a cladding region, a ring core region and an outer glass region is provided, wherein the cladding is provided onto the outer periphery of the center core, and the ring core is provided onto the outer periphery of the cladding, and the outer glass region surrounds the ring core region, and the center core and the ring core have refractive indices higher than the outer glass region and the cladding region has lower refractive index than the outer glass region, and the refractive indices are constrained by the equation n1>n3>n4>n2.
    Type: Application
    Filed: January 22, 2004
    Publication date: March 17, 2005
    Inventors: Shashikant Prasad, Sthitadhi Das, Nageswaran Kumar, Sanjeet Bhatia, Salaj Sinha, Pankaj Khanna
  • Publication number: 20040197063
    Abstract: Dispersion shifted fiber having low dispersion a slope comprising a centre core, two claddings, a ring core and the outer glass region, wherein the first cladding is provided onto the outer periphery of the centre core, the second cladding is provided onto outer periphery of the first cladding and the ring core is provided onto outer periphery of the second cladding, and the outer glass region surrounds the ring core, and the centre core and the ring core have higher refractive indices, and the claddings have lower refractive indices than the outer glass region, and the refractive indices are constrained by the equation n1>n4>n5>n2>n3.
    Type: Application
    Filed: May 17, 2004
    Publication date: October 7, 2004
    Inventors: Samaresh Changdar, Sthitadhi Das
  • Publication number: 20040163418
    Abstract: A method for drawing an optical fiber having reduced polarization mode dispersion (PMD) draws an optical fiber from an optical fiber preform whose core ovality is at max about 3%, coats the optical fiber with acrylic polymer and twists the coated optical fiber with a pair of spinning wheels. The twisting of the fiber is achieved by four discrete spin rates that repeat in a periodic fashion after the drawing of certain lengths of the optical fiber. At least one of the spin rates varies in a trapezoidal manner along the respective one of drawn lengths of the optical fiber.
    Type: Application
    Filed: January 9, 2004
    Publication date: August 26, 2004
    Applicant: STERLITE OPTICAL TECHNOLOGIES LIMITED
    Inventors: Sangeeta Mohanty, Nacham Sridhar, Salaj Sinha, Nitesh Gulati, Sthitadhi Das