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Optical receiving apparatus

  • US 9,379,822 B2
  • Filed: 03/05/2012
  • Issued: 06/28/2016
  • Est. Priority Date: 03/15/2011
  • Status: Expired due to Fees
First Claim
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1. An optical receiving apparatus, comprising:

  • a receiver configured to perform coherent reception by mixing first light of a received optical signal and second light generated by a local oscillator;

    a monitor configured to monitor a first frequency of the first light; and

    a controller configured to control a second frequency of the second light, based on a difference between the first frequency and the second frequency so as to reduce the difference, the controller controlling the second frequency of the second light by;

    adding a difference between the first frequency and second frequency to the second frequency;

    after the adding, determining whether an error occurs in the receiver; and

    when an error occurs in the receiver, sweeping a range for the second frequency so to set the second frequency at a frequency at which the error is removed, the range being determined by subtracting an allowable range of the difference between the first frequency and the second frequency from a sum of a value indicating reliability of the second frequency of the second light generated by the local oscillator and a value indicating reliability of the first frequency of the first light monitored by the monitor.

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