DUPLICATED OPTICAL LOOP NETWORK

摘要

PURPOSE:To constitute right and left both systems by one optical fiber by using a light multiplexer/demultiplexer and light sources of plural wavelengths so as to assign a different wavelength light to the right rotary system and the left rotatary system thereby constituting the duplicated optical loop. CONSTITUTION:An optical signal of wavelength lambda1 is sent in the right rotatary system and an optical signal of a wavelength lambda2 is sent in the left rotary system. The transmission signal of the right rotatary system is led to the light multiplexer/demultiplexer 9 by an optical fiber 8, reproduced into an electric signal by a photoelectric transducer 12 and branched. The branched signal is converted into an optical signal of wavelength lambda1 by an electrooptic transducer 12 together with an insertion signal of the own station and sent to an optical fiber 8' by the light multiplexer/demultiplexer 10. The transmission signal of the left rotary system is led to the light multiplexer/demultiplexer 10 through the fiber 8' after the reproduced into an electric signal by a photoelectric transducer 14 simularly and branched. The branched signal is sent to the optical fiber 8 via an electrooptic converter 11 and the light multiplexer/demultiplexer 9. If a transmission line with the next station of the right rotatary system is failed, the branching signal of the right rotatary system is switched by a changeover switch 15 and sent as the signal of the left rotatary system.