Patents Examined by Steven J. Motola
  • Patent number: 4738503
    Abstract: A fiber optic recirculating memory comprises a splice-free length of optical fiber which forms a loop that is optically closed by means of a fiber optic coupler. The coupler couples an optical signal input pulse to the loop for circulation therein, and outputs a portion of the signal pulse on each circulation to provide a series of output pulses. A pump source is included to pump the fiber loop with a pump signal having sufficient intensity to cause stimulated Raman scattering in the fiber loop, and thereby cause amplification of the circulating signal pulse. The fiber characteristics, coupler characteristics, and a pump power are selected to yield a Raman gain which compensates for the total round-trip losses in the fiber loop, so as to provide an output pulse train of constant amplitude pulses. The invention may be implemented utilizing a standard coupler with a pump signal modulation technique.
    Type: Grant
    Filed: February 12, 1986
    Date of Patent: April 19, 1988
    Assignee: The Board of Trustees of the Leland Stanford Junion University
    Inventors: Emmanuel Desurvire, Michel J. F. Digonnet, Herbert J. Shaw