Optical signal changeover device and optical signal changeover method

Abstract

Disclosed herein are a device and a method for an optical signal changeover that will not necessitate any addition to the capacity of the optical signal selection unit even when the N×M optical switches are expanded in scale, but can keep the optical signal selection unit compact in size and enhance the reliability of the unit. The optical signals received from plural optical transmission lines are converted into predetermined wavelengths by the wavelength conversion unit based on the settings given from the system monitoring control unit. The converted optical signals are bifurcated by the optical bifurcating unit and inputted to the optical switches of the active system and the optical switches of the stand-by system. The optical signals outputted from the optical switches of the active system and from the optical switches of the stand-by system are wavelength-multiplexed by the wavelength multiplexer of the active system and the wavelength multiplexer of the stand-by system and inputted to the 2×1 optical switches of the optical signal selection unit. The optical signal selection unit selects either of the inputted optical signals of the active system or of the stand-by system in accordance with the settings given by the monitoring control unit. The selected wavelength-multiplexed optical signals are demultiplexed by the wavelength demultiplexer into multi-channel optical signals for outputting.