Patents Examined by Welson Moskowitz
  • Patent number: 6747792
    Abstract: A method of amplifying a signal light includes initially multiplexing a signal light and a pumping light, initially amplifying the signal light initially demultiplexing so as to separately output the amplified signal light and the pumping light, and modifying a waveform of the amplified signal light so as to compensate for waveform distortion of the signal light along a transmission path of the signal light and providing an output of a waveform modified signal light. Thereafter, the waveform modified signal lights is secondarily multiplexed, secondarily amplified, and secondarily demultiplexed with a waveform of amplified signal light being compensated for waveform distortion of the signal light along a transmission path of the signal light an output of a waveform modified signal light. The waveform modified signal light is thirdly multiplexed and thirdly amplified so as to provide an output of amplified waveform modified signal light.
    Type: Grant
    Filed: May 28, 2003
    Date of Patent: June 8, 2004
    Assignee: Hitachi, Ltd.
    Inventor: Hiroyuki Nakano
  • Patent number: 5920423
    Abstract: A WDM communication system utilizes a pump-mediated gain-shaped fiber amplifier having a predetermined nominal signal gain bandwidth and is pumped by a plurality of laser pump sources having different wavelength outputs with their outputs combined to provide a scaled power output of a weighted average of their wavelengths for launching into at least one end of the fiber amplifier. The weighted average of the output wavelengths of the individual sources is varied to produced a modified weighted average that broadens the predetermined nominal signal gain bandwidth. The wavelength weighted average of the combined pump sources may be modified by changing the operation of at least one of the pump laser sources, e.g., by changing the power level or the temperature level of one or more of the individual pump sources or by terminating the operation of one or of the individual pump sources.
    Type: Grant
    Filed: December 5, 1997
    Date of Patent: July 6, 1999
    Assignee: SDL, Inc.
    Inventors: Stephen G. Grubb, Bernard G. Fidric
  • Patent number: 5650981
    Abstract: This invention relates generally to a method and system for synchronizing the timing of events between and among vessels using a common timing reference.
    Type: Grant
    Filed: January 6, 1993
    Date of Patent: July 22, 1997
    Assignee: Precision Seismic, Inc.
    Inventors: Nils Erik Jacobsen, Anno Sauer, Ian McMillan, Rolf Ronningen