Optical receiving apparatus
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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Abstract
There is provided an optical receiving apparatus, including 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.
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Citations
6 Claims
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1. An optical receiving apparatus, comprising:
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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. - View Dependent Claims (2)
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3. An optical receiving apparatus, comprising:
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a wavelength de-multiplexer configured to perform wavelength de-multiplexing on a wavelength division multiplexing optical signal; a plurality of receivers configured to perform coherent reception by mixing first light of optical signals having de-multiplexed wavelengths and second light generated by local oscillators, each of the plurality of receivers being arranged corresponding with each of the de-multiplexed wavelengths; a monitor configured to monitor first frequencies of the first light; and a controller configured to control second frequencies of the second light, based on each of differences between the first frequencies and the second frequencies so as to reduce each of the differences, the controller controlling the second frequencies of the second light by; adding a difference between the first frequencies and the second frequencies to the second frequencies, respectively; 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 frequencies so to set the second frequencies at frequencies at which the error is removed, the range being determined by subtracting an allowable range of the difference between the first frequencies and the second frequencies from a sum of a value indicating reliability of the second frequencies of the second light generated by the local oscillator and a value indicating reliability of the first frequencies of the first light monitored by the monitor.
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4. An optical receiving apparatus, comprising:
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a branch unit configured to branch a wavelength division multiplexing optical signal, each of the branched optical signals corresponding with each of a plurality of paths; a plurality of receivers configured to perform coherent reception by mixing first light of optical signals having a wavelength passed from the branched optical signals and second light generated by local oscillators, each of the plurality of receivers being arranged corresponding with each of the plurality of paths; a monitor configured to monitor first frequencies of the first light; and a controller configured to control second frequencies of the second light, based on each of differences between the first frequencies and the second frequencies so as to reduce each of the differences, the controller controlling the second frequencies of the second light by; adding a difference between the first frequencies and the second frequencies to the second frequencies, respectively; 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 frequencies so to set the second frequencies at frequencies at which the error is removed, the range being determined by subtracting an allowable range of the difference between the first frequencies and the second frequencies from a sum of a value indicating reliability of the second frequencies of the second light generated by the local oscillator and a value indicating reliability of the first frequencies of the first light monitored by the monitor. - View Dependent Claims (5, 6)
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Specification