Patent ID: 8078059

Claim:
A multimode optical transmission device for transmitting a multimode optical signal modulated using an information signal to be transmitted, the multimode optical transmission device comprising: an optical transmitting circuit for modulating multimode oscillation light using the information signal, subjecting at least one oscillation-mode light beam of a plurality of oscillation-mode light beams of the modulated multimode oscillation light to a predetermined operation so as to extract predetermined oscillation-mode light from the multimode oscillation light, and outputting the result to an optical transmission channel, the plurality of oscillation-mode light beams being correlated in optical intensity and in optical phase, and each of the plurality of oscillation-mode light beams having a different wavelength; and an optical receiving circuit for receiving an optical signal transmitted through the optical transmission channel, subjecting the received optical signal to an operation reverse to the predetermined operation to recover an optical signal as it was before being subjected to the predetermined operation, and converting the recovered optical signal into an electrical signal, thereby reproducing the information signal, wherein the optical transmitting circuit includes: a multimode light source for outputting the multimode oscillation light; an optical information modulating section for modulating the multimode oscillation light output from the multimode light source using the information signal, and outputting the modulated optical signal; and an optical separating section for receiving the optical signal output from the optical information modulating section, separating the predetermined oscillation-mode light from a plurality of oscillation-mode light beams of the received optical signal, and outputting the predetermined oscillation-mode light to a subsidiary optical transmission channel and a remaining optical signal component other than the predetermined oscillation-mode light of the optical signal to a main optical transmission channel, and the optical receiving circuit includes: an optical intensity detecting section for combining the optical signal component transmitted through the main optical transmission channel and the predetermined oscillation-mode light transmitted through the subsidiary optical transmission channel, and subjecting the result to squared detection to reproduce the information signal.