Optical transmission system, optical receiving apparatus and optical transmission method

An optical reception apparatus configured to demodulate a reception signal by subjecting the reception signal to adaptive equalization processing with a predetermined number of taps, the reception signal being received from an optical transmission apparatus, the optical transmission apparatus being configured to subject a transmission signal including a plurality of sequences to Hadamard transform to obtain a signal in which a predetermined delay is added to one of the plurality of sequences, optically modulate the obtained signal, and transmit the modulated signal, the optical reception apparatus comprising:

• an adaptive equalization processing unit configured to subject the reception signal to adaptive equalization processing of wavelength distortion compensation with a number of taps obtained by subtracting a number determined in accordance with a delay from the predetermined number of taps;
• a delay compensation unit configured to subject the reception signal subjected to the wavelength distortion compensation to delay compensation in accordance with the delay;
• and
• an inverse Hadamard transform unit configured to subject the reception signal subjected to the delay compensation to inverse Hadamard transform.

An optical transmission method in an optical transmission system, the optical transmission system including:

• an optical transmission apparatus configured to subject a transmission signal including a plurality of sequences to Hadamard transform to obtain a signal in which a predetermined delay is added to one of the plurality of sequences, optically modulate the obtained signal, and transmit the modulated signal;
• and an optical reception apparatus configured to demodulate a reception signal received from the optical transmission apparatus by subjecting the reception signal to adaptive equalization processing with a predetermined number of taps, the optical transmission method comprising:
• Subjecting, by the optical reception apparatus, the reception signal to adaptive equalization processing of wavelength distortion compensation with a number of taps obtained by subtracting a number determined in accordance with a delay from the predetermined number of taps;
• Subjecting, by the optical reception apparatus, the reception signal subjected to the wavelength distortion compensation to delay compensation in accordance with the delay;
• and
• Subjecting, by the optical reception apparatus, the reception signal subjected to the delay compensation to inverse Hadamard transform.