Wavelength division multiplexing optical communication system

An optical transmission terminal apparatus for transmitting wavelength division multiplexed signal light in which optical signals of a plurality of bit rates at different wavelength arrangement spacing are arranged in a predetermined signal wavelength band,

• wherein when performing a multiplexing process for multiplexing a plurality of optical signals to generate wavelength division multiplexed signal light, in accordance with a plurality of wavelength regions into which said signal wavelength band is divided on the basis of a wavelength width unit set according to a minimum wavelength arrangement spacing, said optical transmission terminal apparatus includes a multiplexing section capable of setting bandwidth of each optical signal to an integral multiple of said wavelength width unit;
• and said multiplexing section sets said bandwidth of each of the optical signals of different bit rates so as to approximately coincide with wavelength arrangement spacing corresponding to each bit rate.

An optical reception terminal apparatus for transmitting wavelength division multiplexed signal light in which optical signals of a plurality of bit rates at different wavelength arrangement spacing are arranged in a predetermined signal wavelength band,

• wherein when performing a demultiplexing process for demultiplexing wavelength division multiplexed signal light to generate a plurality of optical signals, in accordance with a plurality of wavelength regions into which said signal wavelength band is divided on the basis of a wavelength width unit set according to a minimum wavelength arrangement spacing, said optical reception terminal apparatus includes a demultiplexing section capable of setting bandwidth of each optical signal to an integral multiple of said wavelength width unit and said demultiplexing section sets said bandwidth of each of the optical signals of different bit rates so as to approximately coincide with wavelength arrangement spacing corresponding to each bit rat.

An optical add drop apparatus for adding and dropping optical signals in wavelength division multiplexed signal light in which optical signals of a plurality of bit rates at different wavelength arrangement spacing are arranged in a predetermined signal wavelength band,

• wherein when performing a demultiplexing process for demultiplexing wavelength division multiplexed signal light to generate a plurality of optical signals and a multiplexing process for multiplexing a plurality of optical signals to generate wavelength division multiplexed signal light, in accordance with a plurality of wavelength regions into which said signal wavelength band is divided on the basis of a wavelength width unit set according to a minimum wavelength arrangement spacing, said optical add drop apparatus includes a demultiplexing section and a multiplexing section each capable of setting bandwidth of each optical signal to an integral multiple of said wavelength width unit;
• and each of said demultiplexing section and said multiplexing section sets said bandwidth of each of the optical signals of different bit rates so as to approximately coincide with wavelength arrangement spacing corresponding to each bit rate.