| CPC H04B 10/616 (2013.01) [H04B 10/613 (2013.01); H04B 10/614 (2013.01); H04B 10/60 (2013.01); H04B 10/61 (2013.01); H04B 10/69 (2013.01); H04B 10/693 (2013.01); H04B 10/6931 (2013.01); H04B 10/6933 (2013.01)] | 20 Claims |
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1. A method comprising:
receiving a first optical signal and a second optical signal from a 90 degree optical hybrid that receives a coherent optical signal, wherein the first optical signal and the second optical signal each comprises one pair of sum and difference signals output by the 90 degree optical hybrid;
generating, based on the first optical signal and from a first photo diode, a first differential signal;
generating, based on the second optical signal and from a second photo diode, a second differential signal;
differentially transconducting the first differential signal to produce a first differential transconducted signal;
differentially transconducting the second differential signal to produce a second differential transconducted signal;
performing a differencing operation on the first differential transconducted signal and the second differential transconducted signal to produce a combined differential-differencing transconducted signal that is representative of the first optical signal and the second optical signal; and
outputting the combined differential-differencing transconducted signal as a differential output.
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