High-throughput optical image crossbar switch that uses a point light source array

Voxel is a basic picture element for composing 3D images. Since the generation of each voxel involves at least four pixels from four different view images for the case of full parallax 3D images, any voxel can be generated if the pixel pattern can be found. To find the pixel pattern, a set of voxels with known coordinated values are created by an optical geometry of the point light source array based 3D imaging system. This geometry provides that voxels aligned in planes parallel to the point light source array plane. The pixel pattern corresponding to each voxel is determined as the passage of seeing the point light sources related with the voxel, in the viewing zone. The resulting pixel patterns creates a good 3D image.

Semiconductor optical amplifiers (SOAs) have a number of attractive properties for use in photonic switches. SOAs offer nanosecond switching times, extinction ratios in excess of 40 dB, and small signal gains of approximately 15 dB. In addition they can be monolithically integrated, and thus can potentially be fabricated in volume and used in large switch matrices. Here we report on our recent demonstration of an 8×8 optical crossbar switch based upon discrete SOAs. Other authors [1-3] have reported on SOA-based optical switches at the device level. Our work focuses on the demonstration of the technology at the system level. This demonstration is a significant step towards the widespread use of SOA-based optical switches because it provides a testbed for exploring and identifying the relationships between device parameters and system performance requirements. A block diagram of the optical crossbar switch is shown in Figure 1. The switch is constructed in a modular fashion and consists of optical, digital, analog, and computer modules. Figure 2 shows a photograph of the completed optical crossbar switch.

A three dimensional image (3-D) is synthesized with the use of voxels with known coordinates. Each of these voxels has a corresponding pixel pattern in the display panel. The pattern is found in the optical geometry of the defined viewing zone in contact-type 3-D imaging systems based on a point light source array by assuming that each of the voxels can be seen at any place in the zone. This geometry provides that voxels are aligned in known planes parallel to the array plane. Since each of these voxels is made of rays from specific point light sources, which pass specific pixels in the display panel, the pixel pattern for each voxel is determined as that of the pixels that enable the sources to be seen in the viewing zone through them. The resulting pixel pattern creates a good 3-D image.

360°tabletop floating integral imaging based on spatiotemporal perspective-oriented projecting

We propose a cross-talk-free integral imaging 3D display based on a pyramid pinhole array. The pyramid pinhole array is used to provide a point light source array. Since the generated point light source array is behind a transmission-type display panel that displays an elemental image array, the pseudoscopic problem can be resolved. By setting the appropriate parameters for the pyramid pinhole array, the cross talk can be eliminated. We experimentally verify the reconstruction of the orthoscopic and cross-talk-free 3D images using the proposed 3D display.

We have designed a monolithic 8 X 8 optical crossbar switch that can provide a lossless link for a fiber optic databus or communication system. The device is based upon a semiconductor active (with gain) waveguide structure that can be used as a building block at a monolithic device or multi-device level to configure a high bandwidth space division switch matrix. We have fabricated and characterized a first generation of devices and currently are involved in characterizing the second and designing the third. We will discuss our concepts for applying our device concepts to higher levels of network integration for military and commercial applications.

This paper describes three designs for switched-star networks for computer-system interconnection based on an optical crossbar switch and an electronic controller. These switch designs demonstrate tradeoffs between hardware cost, bandwidth, and latency.KeywordsDestination NodeSetup TimeSwitching SystemShort MessageOptical PlaneThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

An optical crossbar interconnected signal processor, proposed previously, is reviewed. The ability to implement difficult -to-parallelize algorithms on this processor with reasonable efficiency is illustrated using optimal least square filtering. An inversefilter for removing the effects of a ringing source from reflected data is used as an example. A large number of Toeplitz matrixequations must be solved to determine the optimum inverse filter length and phase. Efficient parallel computation is required. Equations for Levinson's algorithm are provided and an implementation on the optical system is suggested. Performance estimates suggest that interleaving may be used to improve efficiency from 5% to approximately 30 %. Introduction An optical crossbar interconnected signal processor was proposed previously that has a large number of processing element.connected via optical fibers to an optical crossbar switch'''. A deformable mirror device is used to construct the crossbar switch.I previously showed how to efficiently implement basic signal processing algorithms such as an FFT, systolic filter, and matrix -

All-optical switching has been considered as a natural choice to keep pace with growing fiber link capacity. One key research issue of all-optical switching is the design of optical buffers for packet contention resolution. One of the most general buffering schemes is optical priority queue, where every packet is associated with a unique priority upon its arrival and departs the queue in order of priority, and the packet with the lowest priority is always dropped when a new packet arrives but the buffer is full. In this paper, we focus on the feedback construction of an optical priority queue with a single (M + 2) × (M + 2) optical crossbar Switch and M fiber Delay Lines (SDL) connecting M inputs and M outputs of the switch. We propose a novel construction of an optical priority queue with buffer 2Θ <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">(√M)</sup> , which improves substantially over all previous constructions that only have buffers of O(M <sup xmlns:mml="http://www.w3.org/1998/Math/MathML" xmlns:xlink="http://www.w3.org/1999/xlink">c</sup> ) size for constant integer c. The key ideas behind our construction include (i) the use of first in first out multiplexers, which admit efficient SDL constructions, for feeding back packets to the switch instead of fiber delay lines, and (ii) the use of a routing policy that is similar to self-routing, where each packet entering the switch is routed to some multiplexer mainly determined by the current ranking of its priority.

The implementation of a large switching network using optical switching technology and components is considered. Optical crossbar switching networks using spatial light modulators (SLMs) offer a solution to the bottleneck of connecting processors, memory modules, and input/output devices in a large parallel processing computer system. >

Summary form only given. Advances in optical devices for applications in broadband telecommunication networks were discussed. Starting with basic optical fibers, semiconductor lasers, and photodetectors, the author covered optical devices for coherent optical communications, optical amplifiers, and optical switching as well as optical passive devices. In addition, advances in optical transmission and switching systems made possible by the evolving optical technologies were discussed as well as their impact on the viability of the broadband telecommunication network. >

This paper presents 1550-nm simulation results on the waveguided silicon-on-insulator four-port optical filtering and switching devices known as "SCISSOR" (an in-line array of microring resonators wherein each ring is coupled to two bus waveguides). We optimized the array number, the ring-bus coupling and the inter-ring spacing in order to obtain "rectangular" filter-passband shapes that have not heretofore been reported in the resonant-optics literature. We were able to engineer a box-like bandpass whose wavelength width could be anywhere from 5 to 50 % of the free spectral range (FSR). We then performed ring-bus apodization of the array that increased side-lobe suppression on the main filter band and widened the band. By reducing the FSR to 2.51 nm with increased ring diameter, we also showed that complete, high-extinction 2 x 2 optical switching is attained when the effective index of each ring in the group is changed by 2 x 10(-3), giving 1.02-nm shift of the 0.77-nm passband. Tunable filtering, sensing, reconfigurable add/drop and wavelength-division demultiplexing is offered in addition to switching.

Introduction: Acquiring a high quality image has assigned an important concern for obtaining accurate diagnosis in nuclear medicine. Detector and collimator are critical component of Single Photon Emission Computed Tomography (SPECT) imaging system for giving accurate information from exact pattern of radionuclide distribution in the target organ. The images are strongly affected by the attenuation, scattering, and response of the detector and collimator. Method and material: The Planar and SPECT scans of a Y90 point source and also an extended Cardiac- Torso(XCAT) computerized phantom with the experiment and simulated systems were prepared. The SIMIND Monte Carlo program was used for simulating Siemen’s dual head variable angle SPECT imaging system with 4 detectors and 10 collimators. After verification and validation of the simulated system, the similar scans of the phantoms were compared from the point of view of image quality for 4 scintillator crystals including: NaI(Tl), BGO, LuAG: Ce, LaBr3 and also 10 collimators: Pb, Pb-Sb, Pb-Sb3, Pb-bi-Sn19, Pb-bi Sn375, Pb-bi-Sn50, Pb-bi-Sn-cd10, Pb-bi-Sn-cd125, Pt and Pt-Co. The parameters of energy and spatial resolution, and sensitivity of the systems were compared. Images were analyzed qualitatively by two nuclear medicine specialists. RESULTS: FWHM of the mentioned crystals and collimators obtained where: NaI (Pb, 0.3853) and BGO (Pb-Sb, 0.406), (Pb-Bi-Sn375, 0.405), (Pb-Bi-Sn-cd125, 0.375), and LuAG: Ce crystal (Pb-Sb, 0.425), (Pb- Bi-Sn19, 0.407), (Pb-Bi-Sn375, 0.417) and also LaBr3 (Pb-Bi-Sn375, 0.407), (Pb-Bi-Sn50, 0.430), (Pt-Co, 0.355). Medical diagnosis of the SPECT images of the phantom showed that the system with NaI(Tl)and LaBr3 by Pb-Sn3 collimator potentially provides a better detectability for hot lesions in the liver of XCAT phantom. CONCLUSIONS: The results showed that crystal NaI(Tl)and LaBr3 by Pb-Sn3 collimator has a high sensitivity and resolution, and also provides a better lesion detectability from the point of view of image quality on XCAT phantom.

An 8/spl times/8 optical switch with a potentially low cost has been designed and fabricated. The switch device, driven by electrostatic force, was made of polymer material using hot embossing process. The optical switch was aligned and assembled together with input and output fibers via grooves etched on a silicon substrate.

Since 1998 the first optical data buses, based on a ring topology and polymethylmethacrylate (PMMA) fibers with 1 mm core diameter and red emitting LEDs were introduced in cars to interconnect information and entertainment components. These systems currently are limited to the passenger compartment, because PMMA fibers do not tolerate environmental temperatures above 85 /spl deg/C, the data rate of these systems is limited to well below 100 MBit/s and the ring topology does not allow the interconnection of safety critical control units. Optical datacom buses based on standard multimode fibers are not useable in cars because of the severe environmental conditions and because of the extremely low-cost demands for in car data transmission systems. We propose and demonstrate a star coupled data bus system based on 200 /spl mu/m core diameter hard clad silica (HCS) fibers for 16 terminals with a data rate of up to 200 MBit/s.