Patent ID: 8463126

Claim:
An optically variable filter array apparatus comprising: an entrance/exit section for a plurality of channels arranged along a y axis, which receives WDM signal light beams of a first to m-th channels, each of which is composed of multi-wavelength light, and allows exit of optical signals of selected wavelengths on a channel to channel basis; a first light condensing element which condenses said WDM signal light beams of different channels; a wavelength dispersion element which spatially disperses said WDM light beams condensed by said first light condensing element according to their wavelengths; a second light condensing element which condenses said WDM light beams of different channels dispersed by said wavelength dispersion element; a wavelength selection element which has a multiplicity of pixels that are arranged in a direction of an x axis according to wavelength, are placed so as to receive incoming beams of m channels arranged at different positions with respect to the y axis so as to be developed over an xy plane, and are arranged in a lattice pattern on the xy plane, and which selects light in a desired number of wavelength bands with respect to said light beams by changing reflection characteristics of each of the pixels arranged in a two-dimensional fashion; and a wavelength selection element driving unit which drives an electrode for each of the pixels arranged in the x-y directions of said wavelength selection element to control light reflection characteristics of a pixel lying at a predetermined position in the x-axis direction as well as in the y-axis direction, wherein at least one of said first light condensing element and second light condensing element is of a concave mirror.