Wavelength division multiplexing optical communication system and wavelength division multiplexing optical communication method

A wavelength division multiplexing optical communication method for transmitting a wavelength division multiplexed optical signal, containing a plurality of optical signals of different wavelengths, from a transmitting terminal station to a receiving terminal station via an optical transmission path, wherein

• in said receiving terminal station, reception information including an optical signal to noise ratio and a transmission error rate for the optical signals of respective wavelengths transmitted through said optical transmission path is measured, and the measured reception information about each wavelength is transmitted to said transmitting terminal station, and
• in said transmitting terminal station, depending on the reception information about each wavelength transmitted from said receiving terminal station, the setting of pre-emphasis to be performed on the wavelength division multiplexed signal light transmitted along said optical transmission path and the setting a parameter a representing an amount of the optical wavelength chirp applied to the wavelength division multiplexed signal light transmitted along said optical transmission path are respectively controlled, wherein the setting of said pre-emphasis is made after controlling the setting of the a parameter representing an amount of the optical wavelength chirp, in a repeating sequence, so that the performed pre-emphasis and applied optical wavelength chirp are controlled together to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed optical signal at the receiving terminal station.

A wavelength division multiplexing communication system for transmitting wavelength division multiplexed signal light containing a plurality of optical signals of different wavelengths, from a transmitting terminal station to a receiving terminal station via an optical transmission path and an optical repeater station, wherein

• said receiving terminal station comprises reception characteristics measurement means for measuring reception information including an optical signal to noise ratio and a transmission error rate for the optical signals of respective wavelengths transmitted through said optical transmission path, and reception information transmission means for transmitting the reception information about each wavelength measured by said reception characteristics measurement means to said transmitting terminal station,
• said transmitting terminal station comprises pre-emphasis performing means for performing pre-emphasis on the wavelength division multiplexed signal light transmitted along said optical transmission path, control means for controlling, depending on the reception information about each wavelength transmitted from said receiving terminal station, the setting of pre-emphasis in said pre-emphasis performing means, and reception information transfer means for transferring the reception information about each wavelength transmitted from said receiving terminal station to said optical repeater station,
• said optical repeater station comprises optical amplification means containing a Raman amplifier for Raman amplifying the wavelength division multiplexed signal light transmitted from said optical transmission path, and Raman amplification control means for controlling a supply condition of Raman excitation light in said Raman amplifier corresponding to the reception information about each wavelength transmitted from said transmitting terminal station, and
• said control means of said transmitting terminal station and said Raman amplification control means of said optical repeater station control the setting of pre-emphasis in said pre-emphasis performing means after controlling the supply condition of Raman excitation light in said Raman amplifier.

A wavelength division multiplexing optical communication method for transmitting a wavelength division multiplexed signal light containing a plurality of optical signals with different wavelengths, from a transmitting terminal station to a receiving terminal station via an optical transmission path and an optical repeater station, wherein

• in said receiving terminal station, reception information including an optical signal to noise ratio and a transmission error rate for the optical signals of respective wavelengths transmitted through said optical transmission path is measured, and the measured reception information about each wavelength is transmitted to said transmitting terminal station,
• in said transmitting terminal station, the reception information about each wavelength transmitted from said receiving terminal station is transferred to said optical repeater station,
• in said optical repeater station, depending on the reception information about each wavelength transmitted from said transmitting terminal station, a supply condition of Raman excitation light for Raman amplifying the wavelength division multiplexed signal light transmitted through said optical transmission path is controlled, and
• in said transmitting terminal station, depending on the reception information about each wavelength transmitted from said receiving terminal station, a setting of pre-emphasis to be performed on the wavelength division multiplexed signal light transmitted through said optical transmission path is controlled.

A wavelength division multiplexing optical communication system for transmitting a wavelength division multiplexed signal light containing a plurality of optical signals with different wavelengths, from a transmitting terminal station to a receiving terminal station via an optical transmission path and an optical repeater station, wherein

• said receiving terminal station comprises reception characteristics measurement means for measuring reception information including an optical signal to noise ratio and a transmission error rate for the optical signals of respective wavelengths transmitted through said optical transmission path, and reception information transmission means for transmitting the reception information about each wavelength measured by said reception characteristics measurement means to said transmitting terminal station,
• said transmitting terminal station comprises pre-emphasis performing means for performing pre-emphasis on the wavelength division, multiplexed signal light transmitted along said optical transmission path, chirp applying means for applying an optical wavelength chirp to the wavelength division multiplexed signal light transmitted along said optical transmission path, control means for controlling said pre-emphasis performing means and said chirp applying means, depending on the reception information about each wavelength transmitted from said receiving terminal station, wherein a setting of the pre-emphasis in said pre-emphasis performing means is after controlling a setting of an a parameter representing an amount of the optical wavelength chirp in said chirp applying means, and reception information transfer means for transferring the reception information about each wavelength transmitted from said receiving terminal station to said optical repeater station,
• said optical repeater station comprises optical amplification means containing a Raman amplifier for Raman amplifying the wavelength division multiplexed signal light transmitted from said optical transmission path, and Raman amplification control means for controlling a supply condition of Raman excitation light in said Raman amplifier corresponding to the reception information about each wavelength transmitted from said transmitting terminal station, and
• said control means of said transmitting terminal station and said Raman amplification control means of said optical repeater station control the setting of the a parameter representing the amount of the optical wavelength chirp in said chirp applying means, and the setting of pre-emphasis in said pre-emphasis performing means, after controlling the supply condition of Raman excitation light in said Raman amplifier so that the performed pre-emphasis, the applied chirp and the Raman amplification are controlled together, in a repeating sequence, to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at said receiving terminal station.

A wavelength division multiplexing optical communication system, comprising:

• a transmitting terminal station having a pre-emphasis performing unit performing pre-emphasis on a wavelength division multiplexed signal light, containing a plurality of optical signals of different wavelength, transmitted along an optical transmission path, a chirp applying unit applying an optical wavelength chirp to the wavelength division multiplexed signal light transmitted along said optical transmission path, and a controller controlling a pre-emphasis setting in the pre-emphasis performing unit, and controlling an a parameter setting representing an amount of the optical wavelength chirp in said chirp applying unit depending on reception information about each wavelength;
• a receiving terminal station having a reception characteristics measurer measuring reception information including optical signal to noise ratio (OSNR) and a transmission error rate of the optical signals of different wavelengths transmitted through said optical transmission path, and a reception information transmitter transmitting the reception information about each wavelength measured by said reception characteristics measurer to said transmitting terminal station,
• wherein the pre-emphasis setting in said pre-emphasis performing unit is made after the a parameter setting, in a repeating sequence, so that the performed pre-emphasis and applied chirp are controlled together to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at the receiving terminal station.

A wavelength division multiplexing optical communication method, comprising:

• transmitting a wavelength division multiplexed signal light, containing a plurality of optical signals of different wavelengths, from a transmitting terminal station to a receiving terminal station via an optical transmission path;
• measuring in said receiving terminal station, reception information including an optical signal to noise ratio and a transmission error rate of the optical signals of respective wavelengths transmitted through said optical transmission path, and transmitting the measured reception information about each wavelength to said transmitting terminal station, and
• controlling in said transmitting terminal station, depending on the reception information about each wavelength transmitted from said receiving terminal station, a pre-emphasis setting to be performed on the wavelength division multiplexed signal light transmitted along said optical transmission path and controlling an a parameter setting representing an amount of the optical wavelength chirp applied to the wavelength division multiplexed signal light transmitted along said optical transmission path,
• wherein the pre-emphasis setting is made after the a parameter setting representing the amount of the optical wavelength chirp, in a repeating sequence, so that the performed pre-emphasis and the applied chirp are controlled together to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at the receiving terminal station.

A method comprising:

• transmitting a wavelength division multiplexed signal light from a transmitting terminal station to a receiving terminal station;
• applying optical wavelength chirp the wavelength division multiplexed signal light by the transmitting terminal station;
• and
• performing pre-emphasis on the wavelength division multiplexed signal light by the transmitting terminal station,
• wherein the applied chirp and performed pre-emphasis are controlled together in accordance with an optical signal to noise ratio and transmission error rate of the wavelength division multiplexed signal light as measured at the receiving terminal station so that the pre-emphasis is performed after the chirp is applied in a repeating sequence to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at the receiving terminal station.

An apparatus comprising:

• means for transmitting a wavelength division multiplexed signal light from a transmitting terminal station to a receiving terminal station;
• means for applying optical wavelength chirp the wavelength division multiplexed signal light by the transmitting terminal station;
• means for performing pre-emphasis on the wavelength division multiplexed signal light by the transmitting terminal station;
• and
• means for controlling the applied chirp and performed pre-emphasis together in accordance with an optical signal to noise ratio and transmission error rate of the wavelength division multiplexed signal light as measured at the receiving terminal station so that the pre-emphasis is performed after the chirp is applied in a repeating sequence to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at the receiving terminal station.

A method comprising:

• transmitting a wavelength division multiplexed signal light from a transmitting terminal station to a receiving terminal station;
• performing Raman amplification of the wavelength division multiplexed signal light;
• performing pre-emphasis on the wavelength division multiplexed signal light by the transmitting terminal station;
• and
• applying chirp to the wavelength division multiplexed signal light by the transmitting terminal station,
• wherein the performed Raman amplification, the performed pre-emphasis and the applied chirp are controlled together in accordance with an optical signal to noise ratio and transmission error rate of the wavelength division multiplexed signal light as measured at the receiving terminal station so that the applied chirp is controlled after the performed Raman amplification is controlled, and the performed pre-emphasis is controlled after the applied chirp is controlled, in a repeating sequence, to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at the receiving terminal station.

An apparatus comprising:

• means for transmitting a wavelength division multiplexed signal light from a transmitting terminal station to a receiving terminal station;
• means for performing Raman amplification of the wavelength division multiplexed signal light;
• means for performing pre-emphasis on the wavelength division multiplexed signal light by the transmitting terminal station;
• means for applying chirp to the wavelength division multiplexed signal light by the transmitting terminal station;
• and
• means for controlling the performed Raman amplification, the performed pre-emphasis and the applied chirp together in accordance with an optical signal to noise ratio and transmission error rate of the wavelength division multiplexed signal light as measured at the receiving terminal station so that the applied chirp is controlled after the performed Raman amplification is controlled, and the performed pre-emphasis is controlled after the applied chirp is controlled, in a repeating sequence, to optimize signal to noise ratio or transmission error rate of the wavelength division multiplexed signal light at the receiving terminal station.