Patent ID: 7346234

Claim:
Optical apparatus for switching multi-channel optical signals having spectral channels of different wavelengths, comprising: a plurality of input and output ports for optical signals having one or more of said spectral channels; an optical beam expander and relay system adapted to receive the optical signals from one or more of the input ports, the optical beam expander and relay system being formed to convert the optical signals to spectral beams having a predetermined elongated beam profile; a wavelength separator for spatially separating the spectral beams into constituent spectral channels; and an array of channel micromirrors, each channel micromirror of the array being positioned to receive one of said constituent spectral channels, the micromirrors being rotatable about a switching axis to switch said one spectral channel to a selected output port; wherein each channel micromirror is rotatable about an attenuation axis to vary coupling of the switched spectral channel to the selected output port to control a power level of the spectral channel output at such selected port, wherein the attenuation axis is different from the switching axis, wherein each channel micromirror is configured to attenuate the power level through a combination of rotations about the switching axis and the attenuation axis sufficient to reduce a non-uniform attenuation of a passband of the apparatus due to diffraction of a spectral beam from an edge of one or more of the micromirrors, wherein the edge is substantially parallel to the attenuation axis, and wherein, for a given level of attenuation of a spectral channel achieved by rotation of the corresponding channel micromirror about the attenuation axis and the switching axis, the corresponding channel micromirror is configured to dither with respect to a dither axis by rotating the corresponding channel micromirror simultaneously about the switching axis and the attenuation axis, wherein the dither axis is approximately tangent to a contour of constant attenuation of the corresponding spectral channel, wherein the contour of constant attenuation represents a plurality of different combinations of rotations of the corresponding channel micromirror about the switching axis and the attenuation axis that achieve the given level of attenuation of the spectral channel.