This paper extends and generalises the rigorous coupled-wave method (for volume-phase holograms), in order to study multiplexed (fan-out) gratings recorded in the same volume. The theory is equally applicable to transmission and reflection gratings replayed with TE polarised light and is consistent with published experimental data. Reflection fan-out holograms are shown to be more efficient and have a higher replay fidelity than their transmission counterparts

The authors report on the production and performance of a holographic nearest neighbour interconnect (NNI) recorded in dichromated gelatin (DCG). The interconnect is for use in a demonstration optical processor, discussed by A.C. Walker et al. (1991), and as such is designed for operation at a wavelength of 1.064 μm

The construction of digital optical processors based on the cellular logic image processor (CLIP) architecture is discussed. Both a single-channel processor and a parallel version incorporating 256 information channels have been constructed. The single channel version of the processor allows eight different combinatorial logic processes to be carried out under electronic control and can be programmed in real time. Several algorithms including pattern recognition, byte comparison, full addition and subtraction have been implemented with this machine. The 256 channel version operates similarly to the single channel version except that a reduced instruction set internal processor with four selectable logic processes is used. A nearest neighbor interconnect provides the communication required between the different information channels. More advanced processing capability can be achieved with the introduction of such non-local interconnects as shuffle networks. Results and simulations obtained with these processors are presented. Advances in the various components of the O- CLIP circuit, future goals, and potential application are also discussed.

Spatially variant interconnects (SVIs), such as the perfect shuffle, crossover and banyan, show great potential in the fields of optical computing and optical communications. Two dimensional forms of these interconnects offer even more power than stacked one dimensional systems. The authors present a method of fabricating such two-dimensional interconnects in a volume holographic material to provide efficient, compact and modular optical interconnection schemes

Spatially variant interconnects (SVIs) show great potential in the fields of optical computing and optical communications. Two dimensional forms of these interconnects offer even more power over their stacked one dimensional1 or wrap around counterparts2.

An optical processor based on the Cellular Logic Image Processor (CLIP) architecture1 has been implemented. The processor incorporates an external input, programmable processing unit, thresholding unit, data synchronisation unit, and an external output (see Fig. 1). All elements of the optical processor are under control of a host electronic computer which also provides the input data and reads the final output result.

Spatially variant holographic optical elements in dichromated gelatin can implement many complicated interconnection patterns and networks in a straightforward manner. We demonstrate some prototype, high efficiency, point to point, off-axis interconnects for replay at the recording wavelength (514.5 nm). Design considerations and potential uses in the fields of optical computing and optical communications are examined. Finally, we suggest a modified approach which allows for on-axis operation and replay in the near infrared.

We demonstrate tI design and fabrication ofarange of space-variant holographic elements(SVHOEs) in dzhromated gelatin (Dcci). These include: a half cmss-over, a perfect shuffle and several butterfly based networks. High diffraction efficiencies (>90%) and near diffractkin limited perfmnance have been hieved. The interconnects link point to point and can be nither on or off-axis in their implemeniation.

We report on the design and fabrication of high diffraction efficiency, high damage threshold space-variant and space-invariant optical fan-out and interconnects in dichromated gelatin (DCG). We have fabricated a range of high efficiency (>90%) lenslet arrays for the visible and near infrared with near diffraction-limited operation capability and excellent uniformity (better than 2 %). In addition we have been successful in combining the flexibility in design of the computer-generated holograms with high diffraction efficiency of DCG to fabricate compact holographic elements which can perform several functions simultaneously. One such device is capable of fan-out, light focusing, and spectral filtering of the input beam. By employing various pre- and postprocessing techniques we have increased the optical damage threshold of these holographic optical elements (HOEs) to >100 W cm −2 . This is of particular importance when large fan-out (>1 → 100 × 100) components are required to power large arrays of optical logic gates.

As a result of research into all-optical digital computing holographic techniques have been developed for producing large arrays of focusing beams to bias optical logic devices, and for interconnecting arrays of devices. These techniques, using dichromated gelatin (DCG) as the holographic medium, can reproducibly provide high performance devices for use at visible wavelengths, and the near infra-red at diode laser wavelengths (850 nm). Details of a 56×56 element lens array recorded at 514 nm for replay at 850 nm are given, as well as those of a space-invariant fanout interconnect hologram for use in an all-optical digital edge-extractor circuit. In addition, a method is given for the post-process tuning of the efficiency of holograms which allows peak efficiency to be achieved in every hologram