An apparatus for selective blocking WDM channels comprises a light modulator,
a diffraction grating, and a transform lens. The light modulator comprises an array
of pixels. Each pixel of the light modulator is selectively operable to direct
light into a first mode and a second mode. The first mode directs the light to
an output. The second mode directs the light away from the output. The diffraction
grating is operable to receive the WDM channels from an input and to disperse the
WDM channels into a range of angles. The transform lens couples the diffraction
grating to the light modulator. The diffraction grating is operable to transform
the range of angles of the WDM channels into a range of spatially distinct positions
along the array of pixels of the light modulator without overlap of two of the
WDM channels on an individual pixel. In operation, the light modulator directs
at least one of the WDM channels into the second mode while directing a remainder
of the WDM channels into the first mode. The light modulator is capable of operating
with a large dynamic range, thereby enabling equalization of select, transmitted
WDM channels as well as blocking any arbitrary channels over the spectral range
of operation.
