Data transmission method and a system thereof

A data transmission system comprising:

• an optical transmitter to generate a transmission optical signal having a frame, the frame including n symbols and containing a pilot signal with fixed amplitude and phase in one of the symbols and a data signal in two or more of the symbols, and to output the transmission optical signal into a transmission line, where n is an integer of 3 or more;
• an optical splitter to split the transmission optical signal received from the transmission line into a plurality of split optical signals;
• a timing signal generator to generate a frame-timing signal from one of the plurality of split optical signals;
• and
• a data separator to separate the data signal from the transmission optical signal received from the transmission line according to the frame-timing signal,
• wherein the data separator comprises:
• a delay interferometer to which a first one of the plurality of split optical signals enters, the delay interferometer having a first optical delay to generate a delayed optical signal corresponding to an integral multiple of a single symbol period;
• and
• a data signal extractor to extract a first data signal in a symbol corresponding to the delayed optical signal according to the frame-timing signal.

A data reception method for receiving data through a transmission optical signal having a frame, the frame including n symbols and containing a pilot signal with fixed amplitude and phase in one of the symbols and a data signal in two or more of the symbols, where n is an integer of 3 or more, the method comprising:

• generating a frame-timing signal from the transmission optical signal;
• and
• separating the data signal from the transmission optical signal according to the frame-timing signal,
• wherein the separating step comprises:
• splitting the transmission optical signal into a plurality of split optical signals;
• delaying a first one of the plurality of split optical signals using an optical delay of a first delay time corresponding to an integral multiple of a single symbol period;
• coupling a second one of the plurality of split optical signals with the delayed split optical signal to generate a coupled optical signal;
• photoelectrically converting the coupled optical signal from into an electrical signal;
• and
• extracting a data signal in a symbol corresponding to the delay time from the electrical signal according to the frame-timing signal.

An optical receiver to receive a data through a transmission optical signal which has a frame as a unit, the frame including n symbols and containing a pilot signal with fixed amplitude and phase in one of the symbols and a data signal in two or more of the symbols, where n is an integer of 3 or more, comprising:

• an optical splitter to split the transmission optical signal received from the transmission line into a plurality of split optical signals;
• a timing signal generator to generate a frame-timing signal from one of the plurality of split optical signals;
• and
• a data separator to separate the data signal from the transmission optical signal received from the transmission line according to the frame-timing signal,
• wherein the data separator comprises:
• a delay interferometer to which a first one of the plurality of split optical signals enters, the delay interferometer having a first optical delay to generate a delayed optical signal corresponding to an integral multiple of a single symbol period;
• and
• a data signal extractor to extract a first data signal in a symbol corresponding to the delayed optical signal according to the frame-timing signal.