Patent ID: 7515830

Claim:
An optical communication apparatus using a sub-carrier multiple access, comprising: a plurality of subscribers, each subscriber comprising a laser diode for generating an optical signal with a central frequency and a temperature control means for controlling a temperature of the laser diode placed at a transmitting terminal; an optical coupling means for combining the optical signal outputted from the laser diode with other optical signals, and outputting a combined optical signal to an optical fiber; an optical receiving means for receiving the combined optical signal outputted from the optical coupling means; a wavelength multiplexing means for multiplexing the optical signal outputted from the optical coupling means with an optical signal outputted from another optical coupling means used for another wavelength bandwidth, the wavelength multiplexing means to form part of a ring network; and a wavelength demultiplexing means for demultiplexing the wavelength multiplexed optical signal outputted from the wavelength multiplexing means, wherein the central frequency of the optical signal outputted from the laser diode is changed in response to the change of the temperature controlled by the temperature control means, such that a central frequency difference between the optical signal and any of the other optical signals is larger than a bandwidth of a sub-carrier signal assigned to the subscriber.