An optical communications apparatus that is superior in terms of the quality
of
long-distance transmission. The optical communications apparatus has a plurality
of time-division multiplexing devices and an optical multiplexer. Each of time-division
multiplexing devices generates optical data sequences by subjecting two systems
of optical signal sequences to time-division multiplexing. In each optical data
sequence, the duty ratio of the optical pulses is 0.5 or greater, and the phase
difference between adjacent optical pulses is phase. Moreover, the optical
multiplexer subjects the optical data sequences input from the plurality of transmitters
to wavelength-division multiplexing. Since the duty ratio is set at 0.5 or greater
and the phase difference is set at phase, the soliton interaction of the
optical signal sequences and the interaction between channels can be reduced, so
that the reliability of the transmitted data is improved.