Apparatus for synchronizing digital signals of coherent optical receiver

A coherent optical receiver comprising:

• an optical hybrid to receive an optical signal transmitted through an optical fiber and an optical signal of laser (hereinafter, referred to as “laser optical signal”) output from a local oscillator and to output the optical signal and the laser optical signal such that the optical signal and the laser optical signal have a predetermined phase difference.
• one or more photo-receivers, each to transform the optical signal and the laser optical signal output from the optical hybrid at a predetermined phase difference into electrical signals;
• an analog-to-digital converter to convert the electrical signals transformed from the optical signal and the laser optical signal into digital signals;
• and
• a digital signal control manager to combine the digital signals converted from the optical signal and the laser optical signal and synchronize the combined digital signals and to decode the synchronized digital signals such that data of the optical signal can be output normally.