Optical communication network system and communication method using the same

Claim 1

An optical communication network system comprising: a base station for simultaneously generating a plurality of continuous beams having different wavelengths; an optical transmission line for transmitting the plurality of beams emitted by said base station; a signal source for generating a communication signal; an optical transmitter, connected to said optical transmission line and said signal source, said optical transmitter including wavelength selection means for selecting a light beam of an arbitrary wavelength among the plurality of light beams transmitted by said optical transmission line and a light beam modulator for modulating the light beam selected by said wavelength selection means in accordance with the communication signal generated by said signal source and multiplexing means for multiplexing the light beam modulated by said light beam modulator to said optical transmission line; and an optical receiver, connected to said optical transmission line, for receiving the communication signal transmitted by the light beam modulated by said light beam modulator.

Claim 40

A method of performing communication using an optical communication network system comprising a base station for simultaneously generating a plurality of continuous beams having different wavelengths, an optical transmission line for transmitting the plurality of beams emitted from said base station, and a plurality of terminal stations connected to said optical transmission line, each of said terminal stations including a signal source for generating a communication signal, an optical transmitter, having a wavelength variable filter and a light beam modulator connected to said signal source, and an optical receiver, comprising the steps of: selecting a beam of a wavelength not being used in other terminal stations among a plurality of beams received by and using an optical receiver of a first one of said terminal stations; selectively demultiplexing the selected light beam with the variable wavelength filter of the first terminal station; modulating the beam selected by said optical receiver of said first terminal station with a light beam modulator of the first terminal station, in accordance with a signal generated by the signal source; transmitting the modulated light beam from said first terminal station through said optical transmission line; and receiving the signal from said first terminal station with an optical receiver of a second one of said terminal stations.

Claim 41

A method of performing communication using an optical communication network system comprising a base station for simultaneously generating a plurality of continuous beams having different wavelengths, an optical transmission line for transmitting the plurality of beams emitted from said base station, and a plurality of terminal stations connected to said optical transmission line, each of said terminal stations including a signal source for generating a communication signal, an optical transmitter, having a wavelength variable filter and a light beam modulator connected to said signal source, and an optical receiver, comprising the steps of: selecting a beam of a wavelength not being used in other terminal stations among a plurality of beams received by and using an optical receiver of a first one of said terminal stations; selectively demultiplexing the selected light beam with the variable wavelength filter of the first terminal station; modulating the beam selected by said optical receiver of said first terminal station with a light beam modulator of the first terminal station, in accordance with a signal generated by the signal source; transmitting the modulated light beam from said first terminal station through said optical transmission line; and receiving the signal from said first terminal station with an optical receiver of a second one of said terminal stations.

Claim 42

A method of performing communication from a first optical transmitter/receiver to a second optical transmitter/receiver in an optical communication network system comprising a base station for generating a plurality of beams having different wavelengths, an optical transmission line for transmitting the plurality of beams emitted by said base station, and a plurality of optical transmitters/receivers connected to said optical transmission line, each of said optical transmitter/receiver being provided with an optical demultiplexing element for demultiplexing parts of the plurality of beams from said optical transmission line, a first wavelength variable filter for selectively extracting a beam having an arbitrary wavelength from the parts demultiplexed by said optical demultiplexing element, a photosensor for detecting the beam extracted by said first wavelength variable filter, a second wavelength variable filter connected to said optical transmission line, for separating a beam having an arbitrary wavelength from said optical transmission line, a signal source for generating a communication signal, an optical modulator connected to said signal source for modulating the beam separated by said second wavelength variable filter, in accordance with the communication signal generated by said signal source, and an optical multiplexing element for multiplexing the beam modulated by said optical modulator to said optical transmission line, comprising the steps of: scanning a wavelength range including wavelengths of the plurality of beams with said first wavelength variable filter of said first optical transmitter/receiver; detecting a beam extracted from said first wavelength variable filter during scanning with said photosensor of said first optical transmitter/receiver, thereby selecting a beam not used in other transmitters/receivers; extracting the selected beam from said optical transmission line with said second wavelength variable filter of said first transmitter/receiver; modulating the extracted light in accordance with the communication signal generated by said signal source; multiplexing the modulated beam to said optical transmission line by said optical multiplexing element of said first optical transmitter/receiver; extracting the selected beam from said optical transmission line with said first wavelength variable filter of said second optical transmitter/receiver; and detecting the extracted beam with said photosensor of said second optical transmitter/receiver, thereby receiving the signal transmitted from said first optical transmitter/receiver.

Claim 43

A method of performing communication from a first optical transmitter/receiver to a second optical transmitter/receiver in an optical communication network system comprising a base station for generating a plurality of beams having different wavelengths, an optical transmission line for transmitting the plurality of beams emitted by said base station, and a plurality of optical transmitters/receivers connected to said optical transmission line, each of said optical transmitter/receiver being provided with an optical demultiplexing element for demultiplexing parts of the plurality of beams from said optical transmission line, a first wavelength variable filter for selectively extracting a beam having an arbitrary wavelength from the parts demultiplexed by said optical demultiplexing element, a photosensor for detecting the beam extracted by said first wavelength variable filter, a second wavelength variable filter connected to said optical transmission line, for separating a beam having an arbitrary wavelength from said optical transmission line, a signal source for generating a communication signal, an optical modulator connected to said signal source for modulating the beam separated by said second wavelength variable filter, in accordance with the communication signal generated by said signal source, and an optical multiplexing element for multiplexing the beam modulated by said optical modulator to said optical transmission line, comprising the steps of: scanning a wavelength range including wavelengths of the plurality of beams with said first wavelength variable filter of said first optical transmitter/receiver; detecting a beam extracted from said first wavelength variable filter during scanning with said photosensor of said first optical transmitter/receiver, thereby selecting a beam not used in other transmitters/receivers; extracting the selected beam from said optical transmission line with said second wavelength variable filter of said first transmitter/receiver; modulating the extracted light in accordance with the communication signal generated by said signal source; multiplexing the modulated beam to said optical transmission line by said optical multiplexing element of said first optical transmitter/receiver; extracting the selected beam from said optical transmission line with said first wavelength variable filter of said second optical transmitter/receiver; and detecting the extracted beam with said photosensor of said second optical transmitter/receiver, thereby receiving the signal transmitted from said first optical transmitter/receiver.

Claim 77

A method of performing communication using an optical communication network system comprising an optical transmission line, a base station, connected to said optical transmission line, for transmitting at least one reference beam having a predetermined wavelength through said optical transmission line, and a plurality of optical transmitters/receivers connected to said optical transmission line, each of said optical transmitters/receivers being provided with a signal source for generating a communication signal, a light source connected to said signal source for transmitting, through said optical transmission line, a signal beam having a wavelength different from that of the reference beam and modulated in accordance with the communication signal generated by said signal source, means for detecting the reference beam, and means for controlling a wavelength of the signal beam emitted from said light source in accordance with the wavelength of the reference beam detected by said detecting means, comprising the steps of: detecting a reference beam transmitted from said base station by said detecting means in said optical transmitter/receiver; transmitting, from said light source to said optical transmission line, a signal beam having a wavelength different from that of the reference beam and modulated in accordance with the communication signal generated by said signal source; and controlling a wavelength of the signal from said light source by said control means on the basis of the wavelength of the reference light beam detected by said detecting means.

Claim 78

A method of performing communication using an optical communication network system comprising an optical transmission line, a base station, connected to said optical transmission line, for transmitting at least one reference beam having a predetermined wavelength through said optical transmission line, and a plurality of optical transmitters/receivers connected to said optical transmission line, each of said optical transmitters/receivers being provided with a signal source for generating a communication signal, a light source connected to said signal source for transmitting, through said optical transmission line, a signal beam having a wavelength different from that of the reference beam and modulated in accordance with the communication signal generated by said signal source, means for detecting the reference beam, and means for controlling a wavelength of the signal beam emitted from said light source in accordance with the wavelength of the reference beam detected by said detecting means, comprising the steps of: detecting a reference beam transmitted from said base station by said detecting means in said optical transmitter/receiver; transmitting, from said light source to said optical transmission line, a signal beam having a wavelength different from that of the reference beam and modulated in accordance with the communication signal generated by said signal source; and controlling a wavelength of the signal from said light source by said control means on the basis of the wavelength of the reference light beam detected by said detecting means.

Claim 79

A method of performing communication from a first optical transmitter/receiver to a second optical transmitter/receiver by using an optical communication network system comprising an optical transmission line, a base station, connected to said optical transmission line, for transmitting at least one reference beam having a predetermined wavelength through said optical transmission line, and a plurality of optical transmitters/receivers connected to said optical transmission line, each of said plurality of optical transmitters/receivers being provided with a first optical element for partially demultiplexing beams transmitted through said optical transmission line from said optical transmission line, a wavelength variable filter for selecting a beam having an arbitrary wavelength from the beams demultiplexed by said first optical element, a photosensor for detecting the beam extracted by said wavelength variable filter, a signal source for generating a communication signal, a light source connected to said signal source for generating a signal beam having a wavelength different from that of a reference beam and modulated in accordance with the communication signal generated by said signal source, a second optical element for outputting the signal light from said light source onto said optical transmission line, and a control circuit for controlling driving of said wavelength variable filter and said light source, comprising the steps of: scanning a wavelength range including the wavelength of the reference beam with said wavelength variable filter in said first optical transmitter/receiver; detecting the beam extracted by said wavelength variable filter during scanning with said photosensor; controlling a filter extraction wavelength to be equal to the wavelength of the reference beam on the basis of an output from said photosensor with said control circuit in said first optical transmitter/receiver; calculating a control signal for said light source on the basis of a filter control signal with said control circuit in said first optical transmitter/receiver; controlling said light source in said first optical transmitter/receiver by using the calculated control signal and sending the signal light from said light source onto said optical transmission line; scanning a wavelength range including the wavelength of the signal light with said wavelength variable filter in said second optical transmitter/receiver; detecting the beam extracted from said wavelength filter during scanning by said photosensor in said second optical transmitter/receiver; controlling the filter extraction wavelength to be equal to the wavelength of the signal beam on the basis of an output signal from said photosensor with said control circuit in said second optical transmitter/receiver; and receiving the signal beam extracted by said filter in said second optical transmitter/receiver with said photosensor, thereby receiving a signal transmitted from said first optical transmitter/receiver.

Claim 80

A method of performing communication from a first optical transmitter/receiver to a second optical transmitter/receiver by using an optical communication network system comprising an optical transmission line, a base station, connected to said optical transmission line, for transmitting at least one reference beam having a predetermined wavelength through said optical transmission line, and a plurality of optical transmitters/receivers connected to said optical transmission line, each of said plurality of optical transmitters/receivers being provided with a first optical element for partially demultiplexing beams transmitted through said optical transmission line from said optical transmission line, a wavelength variable filter for selecting a beam having an arbitrary wavelength from the beams demultiplexed by said first optical element, a photosensor for detecting the beam extracted by said wavelength variable filter, a signal source for generating a communication signal, a light source connected to said signal source for generating a signal beam having a wavelength different from that of a reference beam and modulated in accordance with the communication signal generated by said signal source, a second optical element for outputting the signal light from said light source onto said optical transmission line, and a control circuit for controlling driving of said wavelength variable filter and said light source, comprising the steps of: scanning a wavelength range including the wavelength of the reference beam with said wavelength variable filter in said first optical transmitter/receiver; detecting the beam extracted by said wavelength variable filter during scanning with said photosensor; controlling a filter extraction wavelength to be equal to the wavelength of the reference beam on the basis of an output from said photosensor with said control circuit in said first optical transmitter/receiver; calculating a control signal for said light source on the basis of a filter control signal with said control circuit in said first optical transmitter/receiver; controlling said light source in said first optical transmitter/receiver by using the calculated control signal and sending the signal light from said light source onto said optical transmission line; scanning a wavelength range including the wavelength of the signal light with said wavelength variable filter in said second optical transmitter/receiver; detecting the beam extracted from said wavelength filter during scanning by said photosensor in said second optical transmitter/receiver; controlling the filter extraction wavelength to be equal to the wavelength of the signal beam on the basis of an output signal from said photosensor with said control circuit in said second optical transmitter/receiver; and receiving the signal beam extracted by said filter in said second optical transmitter/receiver with said photosensor, thereby receiving a signal transmitted from said first optical transmitter/receiver.