High-density non-diffracting beam array for optical interconnection

High-density parallel optical beam arrays are useful for free space optical interconnects. To achieve high-density interconnection the optical beam sizes must be small while the propagation divergence within the specified interconnect range must also be small. This contradictory requirement in free space for a conventional Gaussian beam is however possible to be satisfied with a pseudo-non-diffracting beam. We present herein high-density pseudo-non-diffracting beam arrays achieved by using holographic technique. The demonstrated pseudo-non-diffracting beams can keep their central spot size of about 95 μm within the propagation distance of 40 cm. The center-to-center beam separation is 250 μm, which is much smaller than those achieved by collimated Gaussian beams with the same interconnect range. The small central lobe sizes can further avoid the use of collection/focusing lenses at the high-speed photodetector receivers.