Patents by Inventor Robert W. Sadowski

Robert W. Sadowski 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: 5920666
    Abstract: An all-optical fiber switch is implemented within a short Mach-Zehnder interferometer configuration. The Mach-Zehnder switch is constructed to have a high temperature stability so as to minimize temperature gradients and other thermal effects which result in undesirable instability at the output of the switch. The Mach-Zehnder switch of the preferred embodiment is advantageously less than 2 cm in length between couplers to be sufficiently short to be thermally stable, and full switching is accomplished by heavily doping one or both of the arms between the couplers so as to provide a highly nonlinear region within one or both of the arms. A pump input source is used to affect the propagation characteristics of one of the arms to control the output coupling ratio of the switch. Because of the high nonlinearity of the pump input arm, low pump powers can be used, thereby alleviating difficulties and high cost associated with high pump input powers.
    Type: Grant
    Filed: December 30, 1997
    Date of Patent: July 6, 1999
    Assignee: The Board of Trustees for the Leland Stanford Junior University
    Inventors: Michel J. F. Digonnet, H. John Shaw, Richard H. Pantell, Robert W. Sadowski
  • Patent number: 5311525
    Abstract: An optical mode coupling apparatus includes an Erbium-doped optical waveguide in which an optical signal at a signal wavelength propagates in a first spatial propagation mode and a second spatial propagation mode of the waveguide. The optical signal propagating in the waveguide has a beat length. The coupling apparatus includes a pump source of perturbational light signal at a perturbational wavelength that propagates in the waveguide in the first spatial propagation mode. The perturbational signal has a sufficient intensity distribution in the waveguide that it causes a perturbation of the effective refractive index of the first spatial propagation mode of the waveguide in accordance with the optical Kerr effect. The perturbation of the effective refractive index of the first spatial propagation mode of the optical waveguide causes a change in the differential phase delay in the optical signal propagating in the first and second spatial propagation modes.
    Type: Grant
    Filed: March 31, 1992
    Date of Patent: May 10, 1994
    Assignee: The Board of Trustees of the Leland Stanford University
    Inventors: Richard H. Pantell, Robert W. Sadowski, Michel J. F. Digonnet, Herbert J. Shaw