Patent ID: 8873904

Claim:
A wavelength selective switch comprising: at least one input port, for inputting wavelength-multiplexed light; a dispersive element which receives the light from the input port, and disperses the received light; a light converging element which converges the dispersed light for each wavelength; a micro mirror array having a plurality of micro mirrors which are capable of independently deflecting the dispersed light for each wavelength from the light converging element; and at least one output port which receives light which has been deflected by the micro mirror array; wherein at least one of the micro mirrors includes a reflecting surface having a reflectivity distribution; wherein areas having a reflectivity higher than that of a central area of the reflecting surface are formed in at least a part of each end portion of the reflecting surface in a dispersive direction; and wherein each area having a reflectivity higher than that of the central area has a width smaller than a Gaussian beam diameter of a dispersed-light beam incident on the reflecting surface along the dispersive direction and starts from an end of the reflecting surface in the dispersive direction.