Patents by Inventor Yoichi Honzawa

Yoichi Honzawa 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: 7031620
    Abstract: An optical transmission system includes a current source for outputting a drive current, a semiconductor laser for converting the drive current into a stimulated emission light and producing the same, a drive circuit for converting a transmission data signal into a modulation control signal and outputting the same, an optical modulator for receiving the stimulated emission light and a shading control signal for interrupting light emission and producing and outputting transmission signal light by changing an amount of transmission of the stimulated emission light according to the shading control signal, and a shading element for receiving the transmission signal light and a shading control signal for interrupting light emission and interrupting the transmission of the transmission signal light according to the shading control signal whereby an optical signal having wrong optical wavelength is rapidly prevented.
    Type: Grant
    Filed: July 12, 2001
    Date of Patent: April 18, 2006
    Assignee: OpNext Japan, Inc.
    Inventors: Shigeru Tokita, Mitsuo Akashi, Naohiko Baba, Yoichi Honzawa, Hideki Satoh
  • Patent number: 6868235
    Abstract: An optical transmitter receiver module and an apparatus incorporating the same module are provided, which realizes the reduction of power consumption and the enlargement of the operating temperature range.
    Type: Grant
    Filed: September 4, 2001
    Date of Patent: March 15, 2005
    Assignee: Opnext Japan, Inc.
    Inventors: Shigeru Tokita, Tadashi Hatano, Fumihide Maeda, Yoichi Honzawa, Katsumi Saito
  • Patent number: 6693932
    Abstract: In the initial state, any wavelength variation of the output signal light with a change of the current injected into the laser is monitored with a wavelength meter, the quantity of wavelength variation is fed back to the wavelength compensation circuit, a compensation voltage for maintaining the wavelength in the initial stage is figured out, and that voltage is recorded into a memory element or the like. A configuration to add this compensation voltage to a comparator makes it possible to compensate for fluctuations of the characteristics of the optical splitter, wavelength filter and light receiving elements and thereby to obtain a stable optical wavelength. By constantly monitoring the injected current applied to the laser when the optical transmitter is in operation and giving a compensation voltage matching the current variation to the comparator, stabilization of the optical wavelength can be realized.
    Type: Grant
    Filed: June 22, 2001
    Date of Patent: February 17, 2004
    Assignee: Opnext Japan, Inc.
    Inventors: Mitsuo Akashi, Yoichi Honzawa, Sunil Sharma, Shigeru Tokita
  • Publication number: 20020136249
    Abstract: In the initial state, any wavelength variation of the output signal light with a change of the current injected into the laser is monitored with a wavelength meter, the quantity of wavelength variation is fed back to the wavelength compensation circuit, a compensation voltage for maintaining the wavelength in the initial stage is figured out, and that voltage is recorded into a memory element or the like. A configuration to add this compensation voltage to a comparator makes it possible to compensate for fluctuations of the characteristics of the optical splitter, wavelength filter and light receiving elements and thereby to obtain a stable optical wavelength. By constantly monitoring the injected current applied to the laser when the optical transmitter is in operation and giving a compensation voltage matching the current variation to the comparator, stabilization of the optical wavelength can be realized.
    Type: Application
    Filed: June 22, 2001
    Publication date: September 26, 2002
    Applicant: Opnext Japan, Inc.
    Inventors: Mitsuo Akashi, Yoichi Honzawa, Sunil Sharma, Shigeru Tokita, Takayuki Nakao
  • Publication number: 20020061035
    Abstract: An optical transmission system includes a current source for outputting a drive current, a semiconductor laser for converting the drive current into a stimulated emission light and producing the same, a drive circuit for converting a transmission data signal into a modulation control signal and outputting the same, an optical modulator for receiving the stimulated emission light and a shading control signal for interrupting light emission and producing and outputting transmission signal light by changing an amount of transmission of the stimulated emission light according to the shading control signal, and a shading element for receiving the transmission signal light and a shading control signal for interrupting light emission and interrupting the transmission of the transmission signal light according to the shading control signal whereby an optical signal having wrong optical wavelength is rapidly prevented.
    Type: Application
    Filed: July 12, 2001
    Publication date: May 23, 2002
    Applicant: Hitachi,Ltd.
    Inventors: Shigeru Tokita, Mitsuo Akashi, Naohiko Baba, Yoichi Honzawa, Hideki Satoh