Optically cascadable folded perfect shuffle

Abstract

The folded perfect shuffle1 (FPS) was proposed to overcome the space-bandwidth product limitations of 1-D optics. The approach is based on 2-D raster formatting of the input data and an off-axis magnifying imaging system which overlays and shifts the data to the proper format. Pixel interlacing is achieved via subpixel masking, shifted input elements, or shifted imaging lenses. The interconnection patterns comprising a multistage network generally must be cascadable to preclude the need for active interstage regeneration. In a cascadable network both output and input have the same intensity, format, array and pixel dimensions, and beam angles. The previous FPS approach does not meet these criteria. We propose a cascadable implementation of the FPS, based on the original off-axis imaging system, using imaging lenses to provide the proper pixel placement. A 2-D lenslet array is added to correct for the magnification of each data pixel, and a 2-D microprism array generates the1 proper beam angles so that light will not walk out of the system. The architecture has no fundamental light loss, and every stage is identical and possesses lenslet and prism arrays that can be fabricated, in large sizes (e.g., 256 × 256), with current technology.