Publications by authors named "Dominic C O'Brien"

Beam tracking-and-steering is crucial for the operation of high-speed, narrow beam, optical wireless communication (OWC) systems. Using a system based on two sets of low-cost cameras for continuous beam tracking and a set of mirrors for steering, we demonstrate here a high-capacity (>1Tbit/s) ten-channel wavelength-division multiplexed (WDM) OWC system based on discrete multitone transmission. The results, which are achieved over a 3.

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The field of view and gain of optical concentrators used within free space optical communications systems are constrained by conservation of etendue. In this Letter, consideration of the processes in a fluorescent concentrator leads to a simple design strategy for these concentrators for this application. Significantly, because fluorescent concentrators do not conserve etendue, this can lead to concentrators with wider fields of view and higher gains.

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The need for DC balancing phase pixels in ferroelectric liquid-crystal-on-silicon spatial light modulators leads to control schemes that limit their use in beam steering applications where a continuous display of a routing hologram is required. By analyzing the phase redundancy in binary phase holograms, a new DC balancing algorithm has been developed that allows more general beam splitting and multiple beam steering functions. The theoretical derivation of the algorithm and experimentally measured properties of the optical beams are presented and discussed.

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We present an analysis of the performance limit of an adaptive multichannel free-space optical interconnect based on a spatial light modulator (SLM). The SLM function is to provide an active alignment of the signal beam in the detector plane. A thorough cross-talk analysis based on the diffractive properties of an ideal SLM in an isoplanatic optical system is shown.

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We describe the design and analysis of an adaptive free-space optical interconnect between two circuit boards in a standard electronic backplane. An array of vertical-cavity surface-emitting lasers is used as the transmitter, and this communicates with a detector array on the receiver circuit board. Routing is achieved with a holographic crossbar that has a ferroelectric liquid-crystal spatial light modulator to display binary phase computer-generated holograms.

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