Patent ID: 6701090
Filing Date: 2004-03-02
Classification: G02B,H04B,H04J

Abstract:
A wavelength division multiplexing signal number monitoring apparatus for monitoring the number of signal light components (N at the maximum) included in wavelength division multiplexing signal light composed of a plurality of signal light components in which any two signal light components have a wavelength interval therebetween set to an integer multiple of &Dgr;&lgr;i, said apparatus comprising:an arrayed waveguide diffraction grating type optical demultiplexer for guiding said wavelength division multiplexing signal light, demultiplexing thus guided signal light at a wavelength interval of &Dgr;&lgr;o (where &Dgr;&lgr;o=&Dgr;&lgr;i/m, m being an integer of at least two), and outputting demultiplexed individual light components respectively from mÃ—(N+1) (where 1 is a predetermined integer of at least one) different output ports; a light-receiving device array comprising mÃ—(N+1) light-receiving devices disposed so as to correspond to said respective output ports; and a counter unit for receiving an output signal of each light-receiving device of said light-receiving device array and determining the number of signal light components included in said wavelength division multiplexing signal light according to the number of light-receiving devices which have detected light having a predetermined level or higher in each of m light-receiving device groups each combining (N+1) light-receiving devices together such that the light components to be detected have a wavelength interval of &Dgr;&lgr;i.