Abstract: An exemplary embodiment of the invention is a method for evaluating jitter of a phase locked loop circuit generating a phase locked loop output signal. The method includes generating a test initiate signal and generating a trigger signal in response to the test initiate signal. The trigger signal is synchronized with the phase locked loop output signal. A disturbance signal is generated to induce jitter in the phase locked loop output signal. The jitter in the phase locked loop output signal is then evaluated.

Abstract: Apparatus is provided for the readout, and in certain applications the display, of information stored within incoherent/coherent double angularly multiplexed volume holographic optical elements. Such multiplexed volume holographic optical elements are based on parallel incoherent/coherent double angularly multiplexed volume holographic recording and readout principles, and are designed to exhibit maximum optical throughput efficiency and minimum crosstalk. Applications for this novel holographic readout apparatus, when used in conjunction with the aforementioned incoherent/coherent double angularly multiplexed volume holographic optical elements, include photonic interconnections for neural networks, telecommunications switching, and digital computing; optical information processors and optical memories; and optical display systems.

Abstract: Novel multiplexed volume holographic optical elements for the development of highly multiplexed photonic interconnection and holographic memory systems with maximum optical throughput efficiency and minimum crosstalk, based on parallel incoherent/coherent double angularly multiplexed volume holographic recording and readout principles, are disclosed. These principles further provide for arbitrarily weighted and independent interconnections, which are of potential importance in the development of densely interconnected photonic implementations of neural networks, photonic interconnection networks for telecommunications switching and digital computing applications, optical information processors, and optical memories. Utilization of the principles that are key features of this holographic element allows for the single step transfer of all or part of the information stored in a three-dimensional holographic storage device to a second such device in a single exposure step.

Abstract: Computation-intensive applications such as sensor signal processing, sensor fusion, image processing, feature identification, pattern recognition, and early vision place stringent requirements on the computational capacity, size, weight, and power dissipation of modular computational systems intended for both embedded and high performance computer environments. Such ultra high speed, ultra high density computational modules will typically be configured with multiple processor, memory, dedicated sensor, and digital signal processing chips in close-packed multichip modules. The present invention relates to a novel architecture and associated apparatus for the development of highly multiplexed photonic interconnections between pairs of such electronic chips incorporated in vertical stacks within three-dimensional multichip module configurations.

Abstract: A semiconductor chip having an on-chip ground plane comprising a low resistivity semiconductor region in a plurality of non-device regions of the chip and reach-through regions electrically connected to the low resistivity semiconductor region. One or more front-side contacts are used to electrically connect the reach-through regions and the low resistivity semiconductor region to a ground potential to electrically ground the on-chip ground plane.

Abstract: Novel apparatuses for readout of multiplexed volume holographic optical elements, based on parallel incoherent/coherent double angularly multiplexed holographic recording and readout principles, provide for hologram readout with high optical throughput efficiency and minimal crosstalk. Such holographic element readout apparatuses have applications in photonic interconnections for neural networks, telecommunications switching and digital computing; optical information processors and optical memories; and optical display systems. Embodiments are included that allow incoherent superposition of reconstructed images and simplified parallel readout of the volume holographic optical elements. The apparatuses can read out holographic elements that are either optically or computer generated and that are based on continuous-volume or stratified-volume holographic media.

Abstract: The present invention relates to a novel source array comprising a plurality of sources of optical illumination that are at once both individually coherent and mutually incoherent. A primary application of such a source array is to provide the requisite optical source beams in a novel architecture and associated apparatus for the development of highly multiplexed photonic interconnection networks and holographic optical elements with maximum optical throughput efficiency and minimum interchannel crosstalk, based on parallel incoherent/coherent holographic recording and readout principles that are described herein. In one embodiment, the source array is configured from a plurality of coherent sources of illumination; in a second embodiment, a single source of coherent illumination is expanded to illuminate a phase modulator array, within which each separate phase modulator is driven at a distinct oscillation frequency such that the set of resultant modulated beams exhibits mutual incoherence.

Abstract: The present invention relates to a novel spatial light modulator comprising a plurality of individual pixels that each contain separate detectors, electronic circuitry, and optical modulators. A primary application of such a spatial light modulator is to provide the requisite nonlinear relationship between a plurality of optical beams fanned in to each detector on the one hand, and a plurality of optical beams fanned out from such modulator on the other, on a pixel-by-pixel basis. In one embodiment, the spatial light modulator is configured to differentially amplify the inputs to two separate detectors within each pixel, and to transform iORIGIN OF INVENTIONThe U.S. Government has certain rights in this invention pursuant to Contract No. F49620-87-C0007, awarded by the Department of the Air Force, and to Grant No. AFOSR-89-0466, awarded by the Defense Advanced Research Projects Agency through the Department of the Air Force.

Abstract: The present invention relates to a novel architecture and associated apparatus for the development of highly multiplexed photonic interconnection networks and holographic optical elements with maximum optical throughput efficiency and minimum interchannel crosstalk, based on parallel incoherent/coherent holographic recording and readout principles. This scheme further provides for arbitrarily weighted and independent interconnections, which are of potential importance in the development of neuro-optical computers, as well as photonic interconnection networks and multiplexed holographic optical elements. In addition, the extremely difficult problem of copying the contents of a three-dimensional holographic storage device in one step is soluble by utilization of the architectural principles and specified apparatus that are key features of this invention.