Potential of holographically recorded fan-out elements

The paper investigates the recording of efficient off-axis fan-out elements for optical interconnections. The analysis of fan-out elements recorded in volume holograms (coupled wave theory) shows that high efficiency (>90%) and uniformity can be achieved by simultaneous and sequential recording of N object beams. Experimentally, we have achieved 94% efficiency (uniformity error ±5%). The maximum number of fan-out beams and the full fan-out angle are limited by the thickness and by the dynamic range of the holographic emulsion. Optimized recording conditions enable also the realization of high-frequency surface-relief gratings in photoresist which can then be transformed into other materials, like quartz