Patent ID: 8780319

Claim:
A wavelength selective optical switch comprising: an incidence/emergence unit that includes an input port at which signal light made up of light of numerous wavelengths is incident and an output port at which light signals of selected wavelengths are emergent; a wavelength dispersion element that spatially disperses signal light according to a wavelength of the signal light, and synthesizes reflected light; a condenser element that condenses light dispersed by the wavelength dispersion element on a two-dimensional plane; a space phase modulator arranged so as to receive incident light deployed on an xy plane made up of an x-axis direction deployed according to wavelength and a y-axis direction orthogonal to the x-axis direction, and having numerous pixels arranged in a lattice on the xy plane, and uses a multi-level optical phased array that periodically changes a phase shift quantity in the y-axis direction for the pixels on the x-axis in a saw tooth waveform; and a space phase modulator drive unit that drives electrodes of the pixels arrayed in the xy axial directions of the space phase modulator, and reflects light of each wavelength respectively in a plurality of directions, wherein the incidence/emergence unit includes a plurality of input ports and output ports, and when one output port is arranged at a position at which light entering from one input port and reflected from the space phase modulator is incident, other input ports and output ports are arranged at positions that do not correspond to high-order diffracted light thereof.