Patent ID: 7330617

Claim:
A wavelength selective optical switch, comprising: an input and output optical system in which an input port and a plurality of output ports are arranged in a first direction; a spectral element which separates a wavelength division multiplexed light containing a plurality of lights of different wavelengths, which is emitted from the input port in said input and output optical system, according to the wavelengths, to a second direction which is different from said first direction; a condenser optical system which condenses the lights of respective wavelengths separated by said spectral element on different positions; and a mirror array including a plurality of movable mirrors whose angular variable reflecting surfaces are arranged on the condensing positions of the lights of respective wavelengths condensed by said condenser optical system, in which angles of the reflecting surfaces of said movable mirrors are controlled, so that the lights of respective wavelengths reflected by said respective movable mirrors are guided, via said condenser optical system and said spectral element, to the output ports which correspond to the lights of respective wavelengths, among the plurality of output ports in said input and output optical system, wherein said condenser optical system includes a plurality of lenses whose focal distances are different from each other, and is provided with a slide mechanism which makes at least one of said plurality of lenses movable in parallel to an optical axis direction which is orthogonal to said first and second directions, so that the lights of respective wavelengths have a beam pitch on the condensing positions thereof that coincides with a mirror pitch of the movable mirrors of said mirror array.