Optical communication base station, optical signal conversion apparatus, and optical signal conversion method

An optical signal conversion apparatus for converting a first optical signal into a fixed bit-rate second optical signal, said first optical signal being received from each one of a plurality of communication units that transmit optical signals at different bit rates, said apparatus comprising:

• an optical-to-electrical conversion unit which converts said first optical signal into an electrical signal;
• a code decision unit which makes code decisions on said electrical signal at a provisional decision clock frequency corresponding to a bit rate equal to an integral multiple of the highest of the bit rates that said plurality of communication units use;
• a storage unit which temporarily stores a code sequence obtained as a provisional code sequence by said code decisions;
• a code correction unit which regenerates an original code sequence by correcting code sequence length of said provisional code sequence temporarily stored in said storage unit;
• and
• a bit rate detection unit which detects the bit rate of said first optical signal based on a length of a receiving period of said provisional code sequence generated from a fixed bit length preamble of said first optical signal,
• wherein using said bit rate detected by said bit rate detection unit, said code correction unit corrects the code sequence length of said provisional code sequence temporarily stored in said storage unit.

An optical signal conversion method for converting a first optical signal into a fixed bit-rate second optical signal, said first optical signal being received from each one of a plurality of communication units that transmit optical signals at different bit rates, said method comprising:

• converting said first optical signal into an electrical signal;
• making code decisions on said electrical signal at a provisional decision clock frequency corresponding to a bit rate equal to an integral multiple of the highest of the bit rates that said plurality of communication units use;
• temporarily storing in a specified storage unit a code sequence obtained as a provisional code sequence by said code decisions;
• detecting the bit rate of said first optical signal based on a length of a receiving period of the provisional code sequence generated from a fixed bit length preamble of said first optical signal,
• regenerating an original code sequence by correcting code sequence length of said provisional code sequence temporarily stored in said storage unit based on the bit rate detected;
• and
• generating said second optical signal by modulating prescribed carrier light with said original code sequence.