Optical add-drop multiplexer architecture with reduced effect of mirror edge diffraction

摘要

Effects of diffraction of a spectral beam from an edge of the micromirrors are reduced in order to optimize the passband in a wavelength selective switch. The effects of diffraction on the pass band may be reduced by appropriate modification of the edges of the micromirrors, by modification of the input and/or output ports to allow for attenuation by rotation of the micromirror about the switching axis, by using rotation of the micromirror about both the attenuation axis and the switching axis to achieve the desired level of attenuation, by inserting an aperture at a focal plane or external to the device to reduce the magnitude of the micromirror edge diffraction transmitted to any or all output ports, or by appropriate filtering of angular frequencies with a diffraction grating used to separate a multi-channel optical signal into constituent spectral beams.