Dual grating filtering system

1. Field of the Invention A light filtering assembly for filtering an input beam of light having a plurality of desired wavelength components and a plurality of unwanted wavelength components so as to provide an output beam having only the desired wavelength components. The filtering assembly comprises an input section, a filtering section, and an output section. The input section divides the input beam into a plurality of polarized beamlets that travel along a corresponding plurality of spatially separated beam paths. The polarized beamlets comprise a plurality of desired beamlets corresponding to the desired wavelength components of the input beam and a plurality of unwanted beamlets corresponding to the unwanted wavelength components of the input beam. The filtering section is disposed in the paths of the beamlets so that the desired beamlets are passed and the unwanted beamlets are blocked. The output section is disposed in the paths of the desired beamlets exiting the filtering section and combines the desired beamlets so as to form the output beam. The output section is substantially identical to the input section to provide bi-directional capabilities. Because the beamlets are linearly polarized, the input and output sections are able to realize a high throughput efficiency.