The authors take the approach that the beam splitter design has to be carried out fully in two dimensions. They have made a number of binary phase gratings that operate in the Fourier plane, next to a focusing lens or...
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The authors take the approach that the beam splitter design has to be carried out fully in two dimensions. They have made a number of binary phase gratings that operate in the Fourier plane, next to a focusing lens or lens pair. The elements are designed to change the single focused spot into an array of spots with a given distribution of intensity and given separation. They are only interested in the intensity distribution in the focal plane, and therefore the distance between the focusing lens and the grating is unimportant.< >
The authors deal with the recording of 125 mu m diameter holographic lenses in silver halide emulsion to operate in the 1200-1600 nm region, for optical fibre interconnect applications. Holographic materials are only ...
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The authors deal with the recording of 125 mu m diameter holographic lenses in silver halide emulsion to operate in the 1200-1600 nm region, for optical fibre interconnect applications. Holographic materials are only sensitive to visible light. This requires that recording is at a different wavelength from replay. Lenses recorded at 514.5 nm were replayed at 1500 nm. Results of this replay have been given in the form of a scaled image of the focal region and an indication of the lenses efficiency in coupling light from one fibre into another.< >
Photoresist is often regarded as a binary medium in that once it has been exposed to a suitable pattern of light and developed, it either remains or is totally removed to reveal a clear substrate. However, by using al...
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Photoresist is often regarded as a binary medium in that once it has been exposed to a suitable pattern of light and developed, it either remains or is totally removed to reveal a clear substrate. However, by using alternative processing techniques, it is also possible to generate a range of continuous profiles within the limits imposed by the thickness of the resist. This has been used in the manufacture of spectroscopic diffraction gratings and certain display holograms. The authors consider extending the techniques to the manufacture of some of the components required by developments in electro-optics and optical data handling. In particular, they consider microlens arrays and fan-out gratings.< >
作者：
C. SlingerEM1 Division
Scottish Power Public Limited Company Great Malvern Worcestershire UK
In practice, adaptive networks generally require a large number of processing nodes, the output of each being passed, via a weighted interconnection, to many of the other nodes. Thus a network of 10/sup 4/ nodes can r...
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In practice, adaptive networks generally require a large number of processing nodes, the output of each being passed, via a weighted interconnection, to many of the other nodes. Thus a network of 10/sup 4/ nodes can require up to 10/sup 8/ individually weighted interconnections. The situation is further complicated by the requirement that independent updating of the weight values is needed during network optimisation. A quantitative analysis is attempted, with a view to assessing the usefulness of an interconnect scheme using multiple grating volume holograms for adaptive network applications. The main question to be answered concerns the fidelity of the system i.e. the degree to which the desired weighted interconnections can be achieved.< >
Many schemes for parallel optical interconnects involve the use of spatial light modulators (SLMs). Advances have occurred in liquid crystal technology that promise major improvements in the performance of SLMs. These...
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Many schemes for parallel optical interconnects involve the use of spatial light modulators (SLMs). Advances have occurred in liquid crystal technology that promise major improvements in the performance of SLMs. These are not based on electro-optic effects in the familiar nematic and cholesteric phases, but on a number of newer electro-optic effects in chiral smectic liquid crystals. The authors examine two of these electro-optic effects; the so called ferroelectric switching in chiral smectic C liquid crystals and electronic switching in chiral smectic A phases. They assess their prospects in electrically addressed spatial light modulators and emphasise the problems of obtaining in large arrays of pixels the same performance as can be obtained from single pixels. A hybrid technology, combining chiral smectic liquid crystals and silicon VLSI, is proposed as a means of obtaining addressable structures of large arrays of pixels. The problems and prospects of this hybrid technology are briefly reviewed.< >
The authors describe a programmable optical interconnect device for use in 2D optical information processing systems. They have concentrated on the moderately rapidly reconfigurable type as this approach is likely to ...
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The authors describe a programmable optical interconnect device for use in 2D optical information processing systems. They have concentrated on the moderately rapidly reconfigurable type as this approach is likely to yield a useful and flexible interconnection system with present available optical technology. The type of system considered uses a device which consists of a 2-D array of independent electrooptically induced diffraction gratings. This approach is novel in that it combines the highly parallel 2-D array capabilities of a static holographic interconnect approach with the ability to reconfigure the interconnection pattern. The induced diffraction gratings are used to diffract information carrying beams of light to any desired output location. As all the gratings in the 2-D array are completely independent the device can support all possible interconnection patterns between the input and output locations.< >
A model for reconfigurable networks is presented in a formal setting with respect to the general underlying topologies. A reconfigurable network is superior to traditional communication (fixed-connection) networks and...
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A model for reconfigurable networks is presented in a formal setting with respect to the general underlying topologies. A reconfigurable network is superior to traditional communication (fixed-connection) networks and to several other communication and computation models only if the transmission time is constant, regardless of the number of switches and links through which the message has to pass in the underlying architecture. This is not the case for switches using semiconductors technology. A zero-latency optical implementation for such networks, using existing guided-optic devices, is proposed. To demonstrate the power of the model, algorithms and lower bounds for computing SUM and its variants are considered. It is shown, using simple underlying topologies, that a reconfigurable machine completes such computations faster than any other realizable model and many other nonrealizable models. In particular, it is shown how to compute ranking and how to sort N keys in constant time on the N*N*N reconfigurable cube.< >
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