Patents by Inventor Kazue Otsuka

Kazue Otsuka 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).

  • Reference light source device using laser
    Patent number: 5440207
    Abstract: A reference light source device includes a first laser diode emitting a reference light, a harmonic generating unit for generating an nth harmonic of the reference light, where n is an integer, a light generating unit for generating a light signal having a waveform equal to that of the nth harmonic of the reference light, and a photodetector for combining the nth harmonic and the light signal and for generating a first electric signal corresponding to a beat signal obtained by combining the nth harmonic and the light signal. Further, the source device includes a local signal generating unit for generating a local signal, a phase comparator for generating a control signal corresponding to a phase difference between the first electric signal and the local signal, and a driving unit for driving the first laser diode according to the control signal so that a frequency of the beat signal is equal to that of the local signal.
    Type: Grant
    Filed: November 4, 1993
    Date of Patent: August 8, 1995
    Assignee: Fujitsu Limited
    Inventor: Kazue Otsuka