Optical communications – Receiver – Heterodyne
Reexamination Certificate
2011-06-07
2011-06-07
Liu, Li (Department: 2613)
Optical communications
Receiver
Heterodyne
C398S202000, C398S204000, C398S206000, C398S213000, C398S152000
Reexamination Certificate
active
07957654
ABSTRACT:
A coherent optical receiver of the invention combines local oscillator light having orthogonal polarization components in which the optical frequencies are different to each other, and received signal light, in an optical hybrid circuit, and then photoelectrically converts this in two differential photodetectors. Then this is converted to a digital signal in an AD conversion circuit, and computation processing is executed in a digital computing circuit using the digital signal, to estimate received data. At this time, the optical frequency difference between the orthogonal polarization components of the local oscillator light is set so as to be smaller than two times the signal light band width, and larger than a spectrum line width of the signal light source and the local oscillator light source. As a result, it is possible to realize a small size polarization independent coherent optical receiver that is capable of receiving high speed signal light.
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Fujitsu Limited
Fujitsu Patent Center
Liu Li
LandOfFree
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