Patent ID: 7734196
Filing Date: 2010-06-08
Classification: H04B

Abstract:
1. An optical receiver device for receiving an optical signal modulated using differential quadrature phase shift keying, the optical receiver device comprising: a split device to split a received optical signal into two optical signals; a first photoelectric conversion device to extract a first phase modulation component from one of the two optical signals, and to convert the first phase modulation component into a first data signal; a second photoelectric conversion device to extract a second phase modulation component from the other one of the two optical signals, and to convert the second chase modulation component into a second data signal; a clock recovery device to extract a clock signal from one of the first data signal and the second data signal, and to output an extracted clock signal; an inversion device to generate an inverted clock signal by inverting the extracted clock signal, to select one of the extracted clock signal and the inverted clock signal depending on a differential delay between the first data signal and the second data signal, and to output the selected clock signal; a delay device to delay the extracted clock signal by a delay amount equivalent to ¼ of a time slot of one of the first data signal and the second data signal, and to output a delayed clock signal; a first decision device to latch the first data signal by using the clock signal output from the inversion device; and a second decision device to latch the second data signal by using the delayed clock signal, wherein: the inversion device selects and outputs one of the extracted clock signal and the inverted clock signal according to a control signal and selects and outputs the extracted clock signal when there is not a differential delay between the first data signal and the second data signal and when the second data signal has a delay amount equivalent to ½ of a time slot to the first data signal, and the inverted clock signal when the first data signal has a delay amount equivalent to ½ of a time slot to the second data signal.