Optical information processing can perform a myriad of signal processing operations. It is primarily due to the complex amplitude processing capability. Optical information processors are capable of performing one- or two-dimensional operations using simple linear operators. However, it would not happen without the support of coherent property of illumination. In this paper we shall discuss the inherent optical complex transformation, by which information data processing can be exploited. Fourier and spatial domain processing, composite filtering, 3-D pattern recognition, larger capacity photo-refractive processing optical neural computing and others will be stressed.

We have investigated various conductive and non-conductive polymers suitable for use as cladding layers in nonlinear optic (NLO) polymer based opto-electronic devices. Our goal was to maximize the nonlinearity of the core material, minimize the total poling voltage, and minimize the absorption loss. Using a cladding material that is more conductive than the NLO core material, the majority of the applied poling voltage is dropped across the core, realizing a maximum EO coefficient with minimum applied voltage. We found, however, that there are tradeoffs between absorption loss, conductivity, refractive index, materials processability and materials compatibility when using off-the-shelf materials.

A hybrid scalable optoelectronic crossbar switching system that uses global parallel free-space optical interconnects and three-dimensional (3D) VLSI chip stacks is presented. The system includes three 3D chip stacks with each consisting of 16 VLSI chips. A single 16 X 16 VCSEL/MSM detector array is flip-chip bonded on top of the chip stack. Each chip supports 16 optical I/Os at 1 Gb/s. For the free-space optical interconnection between the chip stacks, a novel folded hybrid micro/macro optical system with a concave reflection mirror has been designed. The optics module can provide a high resolution, large field of view, high link efficiency, and low optical crosstalk. It is also symmetric and modular. Off-the- shelf macro-optical components are used. The concave reflection mirror can significantly improve the image quality and tolerate a large misalignment of the optical components. Scaling of the macrolens can be used to adjust the interconnection length between the chip stacks. The optical system is analyzed based on ray-tracing and scalar diffraction theory. The impact of Ghost talk on high-speed optical interconnection is studied. For system packaging, only passive alignment is required. Optics and electronics are separated until final assembly step, and the optomechanic module can be removed and replaced. By using 3D chip stacks, commercially available optical components and simple passive packaging techniques, it is possible to achieve a high-performance optoelectronic switching system.

Optical communication is invading short distance communication (e.g. private networks etc.) as well as the digital computer backplane. Many optical devices have already been developed for these applications and many other newer devices are emerging. Possible optical devices for private networks and computer backplane are reviewed, and their deployment in different applications are also cited.

This paper reviews our recent work on various planar-waveguide-type optical switching devices. Specifically we investigated N x N thermo-optic (TO) matrix switches. The matrix switch consists of N² switching units and the switching unit has two cascaded Mach-Zehnder interferometers (MZIs). Switching is achieved by using a phase control technique based on the TO effect. The switching power of an MZI unit and the switching speed are typically 0.4 W and 2 ms, respectively. For N equals 16, we realized non-blocking connection with a very low-loss of 6.6 dB and a high-extinction ratio of 55 dB. We have also developed 1 x N configuration switches for use in optical path cross-connect systems. By integrating TO switches and arrayed-waveguide grating multi/demultiplexers, we fabricated single-chip optical add/drop multiplexers (OADM) for use in all-optical wavelength division multiplexing (WDM) routing systems. We have developed a power consumption reduction technique that is effective for all MZI TO switches as regards large scale integrated switch applications.

We investigate the recent trends and advancements in real time pattern recognition with special reference to joint transform correlator (JTC) architectures and algorithms. Techniques for achieving both single and multiple target detection in noise-free, noisy and cluttered input scenes using the classical, binary and fringe-adjusted JTCs are discussed. Distortion invariant target recognition using tools such as the synthetic discriminant function is also incorporated. Various optoelectronic and all-optical architectures and implementation issues for effectively implementing the various types of JTC techniques are discussed. Extensive simulation results are presented to investigate the effectiveness of the various JTC techniques, especially the fringe-adjusted JTC.

Optical logic cells, employed in several tasks as optical computing or optically controlled switches for photonic switching, offer a very particular behavior when the working conditions are slightly modified. One of the more striking changes occurs when some delayed feedback is applied between one of the possible output gates and a control input. Some of these new phenomena have been studied by us and reported in previous papers. A chaotic behavior is one of the more characteristic results and its possible applications range from communications to cryptography. But the main problem related with this behavior is the binary character of the resulting signal. Most of the nowadays-employed techniques to analyze chaotic signals concern to analogue signals where algebraic equations are possible to obtain. There are no specific tools to study digital chaotic signals. Some methods have been proposed. One of the more used is equivalent to the phase diagram in analogue chaos. The binary signal is converted to hexadecimal and then analyzed. We represented the fractal characteristics of the signal. It has the characteristics of a strange attractor and gives more information than the obtained from previous methods. A phase diagram, as the one obtained by previous techniques, may fully cover its surface with the trajectories and almost no information may be obtained from it. Now, this new method offers the evolution around just a certain area being this lines the strange attractor.

In this paper, a new algorithm to determine the adaptive threshold formula for the trinary associative memory model is presented. The optimal threshold is chosen to yield the best performance. Different threshold parameters have been investigated to obtain the optimal range of threshold parameters. In order to validate our performance model, character recognition problems are investigated.

We proposed an optical communications system, based on a digital chaotic signal where the synchronization of chaos was the main objective, in some previous papers. In this paper we will extend this work. A way to add the digital data signal to be transmitted onto the chaotic signal and its correct reception, is the main objective. We report some methods to study the main characteristics of the resulting signal. The main problem with any real system is the presence of some retard between the times than the signal is generated at the emitter at the time when this signal is received. Any system using chaotic signals as a method to encrypt need to have the same characteristics in emitter and receiver. It is because that, this control of time is needed. A method to control, in real time the chaotic signals, is reported.

This paper presented an optical interconnection multiple PC system connected by a ring network. This multiple PC system uses Linux Operating system, and the standard communication protocol of complying with Ethernet specification. This paper studied the factors that influence the interconnection performance among multiple computers, including the effect of the buffer size of OLI on the bandwidth of network layer, and the effect of retransmission method on the performance. The results of ping-pong test show that optical fiber link is able to provide high-bandwidth and low-latency communication for a multi-PCs system. We found that the performance of the interconnection network can be improved by improving the interface match between the optical fiber link and computer bus input/output. Besides, the development of a chip to implement network interface and a part of network protocol, such as developing with FPGA device in this paper, could result in the higher performance of the interconnection.

A major drawback of lightwave circuits (LWCs) is the nearest- neighbor (NN) interconnection scheme. An attempt to overcome within the technological restrictions is the repetitive triangulation (RTR) of the proposed N-gon cell complexes. (Higher-order RTR is aimed to be done in the frequency domain.) The 2-D LWCs are analyzed by (1) 2-D models (projection onto the plane) and (2) 3-D models. The 2-D models are (a) orthogonal 2-D grids where faulty edges comes in and (b) double triangulated 2-D grids for the embedding of the N- gon cell complexes subject to RTR. The 3-D models are (i) orthogonal 3-D grids and (ii) orthogonal 3-D grids with triangulated plane facets as spatial triangulation causes a topology which is difficult to realize by LWCs. The random walks within these architectures are considered. Random walks in orthogonal grids are known to exhibit different properties dependent on the dimension. These properties have to do with the propagation in all 2d directions (d is the dimension). The question arises whether these properties are obtainable also within the proposed feed-forward (FF) networks where backward couplings are excluded. As an approach to control these random walk characteristics (synthesis) the biased random walk is proposed.

A nonpixelized electrically addressable spatial light phase- only modulator has been developed. The device consists of an optically addressed parallel aligned nematic liquid crystal spatial light modulator (PAL-SLM), coupling optics, an XGA liquid crystal display (LCD) which serves as an accurate addressable mask for the PAL-SLM, a laser diode (LD) for illuminating the LCD and collimating optics for the LD. The device has a phase modulation capability of over 2(pi) radians and a high diffraction efficiency of greater than 35% at a spatial frequency of 10 lp/mm of binary (0,(pi) ) grating. Also when a multilevel (0, 0.5(pi) , (pi) , 1.5(pi) ) grating was written in the device, a diffraction efficiency of greater than 70% at a spatial frequency of 10 lp/mm was obtained. Moreover, surplus diffraction light (diffraction noise) caused by the pixelized structure was reduced to less than 3% by the coupling optics, compared with almost 50% occurring in the LCD by itself.

Optical processing is supposed to be advantageous in very big problems, because it can handle those problems with minimal spatial and temporal complexity. What happens, though at the other extreme, where the problem is too big to be input into the optical system? I offer some preliminary thoughts here.

Angular and wavelength READ beam errors in holographic interconnection systems are often a recurrent problem. Several strategies have been proposed to minimize or eliminate such READOUT misalignments. Some years ago, Chatterjee and co-workers proposed a method involving READ beam wavelength tuning to correct output angular errors. In this paper, we investigate the possibility of using an acousto-optic (A-O) Bragg cell with optoelectronic feedback to dynamically correct the scattered beam for deviations in the incidence direction of the READ beam of a hologram. The concept here is based on an acoustic frequency feedback strategy used recently by Balakshy and Kazaryan for laser beam directional stabilization. In the dynamic and adaptive method being proposed here, an acousto-optic Bragg cell is placed between the READ beam and the hologram. A photo-detector placed after the Bragg cell enables the estimation of scattered efficiency and hence (from the READ dephasing-based diffraction efficiency), the amount of the angular deviation. An algorithm for implementing the above scheme, to be used in a practical setup, is proposed and the results of numerical simulations are presented along with possible extensions to wavelength error correction and other applications.

Inductively coupled plasma (ICP) equipment is a new advanced version of dry-etching equipment that has not been widely reported to produce micro-optical elements before. The obvious structural improvement of ICP over the usual widely-used Reactive Ion Etching (RIE) is that two Radio Frequency (RF) power sources are used in ICP, while only one RF power source is used in RIE. This structural improvement of ICP results in the features of high-density plasma, low pressure and good directionality of ions, thereby bringing us the advantages over RIE technology as the weaker surface damage, better vertical profile of the etched surface, smaller linewidth and more freedoms to control the etching process. In this paper we report our detailed experimental results of using the new ICP setup for producing micro-optical elements. Experimental results support the view that ICP is a new advanced version of dry etching equipment for producing micro-optical elements. Phase gratings made with ICP have wide applications in micro-optical elements and systems. It is believed that use of ICP is the new developing direction for fabrication of micro- optical elements and systems in the future.

This research explores architectures and design principles for monolithic optoelectronic integrated circuits (OEICs) through the implementation of an optical multi-token-ring network testbed system. Monolithic smart pixel CMOS OEICs are of paramount importance to high performance networks, communication switches, computer interfaces, and parallel signal processing for demanding future multimedia applications. The general testbed system is called Reconfigurable Translucent Smart Pixel Array (R-Transpar) and includes a field programmable gate array (FPGA), a transimpedance receiver array, and an optoelectronic very large-scale integrated (OE-VLSI) smart pixel array. The FPGA is an Altera FLEX10K100E chip that performs logic functions and receives inputs from the transimpedance receiver array. A monolithic (OE-VLSI) smart pixel device containing an array of 4 X 4 vertical-cavity surface-emitting lasers (VCSELs) spatially interlaced with an array of 4 X 4 metal- semiconductor-metal (MSM) detectors connects to these devices and performs optical input-output functions. These components are mounted on a printed circuit board for testing and evaluation of integrated monolithic OEIC designs and various optical interconnection techniques. The system moves information between nodes by transferring 3-D optical packets in free space or through fiber image guides. The R-Transpar system is reconfigurable to test different network protocols and signal processing functions. In its operation as a 3-D multi-token-ring network, we use a specific version of the system called Transpar-Token-Ring (Transpar-TR) that uses novel time-division multiplexed (TDM) network node addressing to enhance channel utilization and throughput. Host computers interface with the system via a high-speed digital I/O board that sends commands for networking and application algorithm operations. We describe the system operation and experimental results in detail.

A technique for an all-optical storage of multi-bit binary words in the form of 'bright' guiding-center solitons is presented. This technique has its origin in previously elaborated method of additive active mode-locking. An improved description of additive active mode-locking regime in semiconductor laser with an external fiber cavity is developed and analytical solution to this problem in steady-state regime is found with due regard for the phase effects. Picosecond optical guiding-center solitons of the first order, inherent in the systems of Ginzburg-Landau type, are considered as the bit carriers. Here, the model, described by the complex cubic Ginzburg-Landau equation, is analyzed and a new approximate analytical description in terms of Gaussian functions for the evolution of the main parameters of 'bright' guiding-center solitons in optical fiber is presented. The technique under consideration is based on matching the parameters of optical pulses in semiconductor laser structure by the parameters of guiding-center solitons in single-mode fiber. Some performance data of the memory device, maintaining the non-stop circulation guiding-center soliton digital trains and providing both all-optical and electronic access to the memory, are estimated.

The transmission theory of laser polarization is applied to the electro-optical switching system. The polarization transmission matrix in Electro-optical switching system is given. The switching property through the system is analyzed.

Appropriate segmentation of video is a key step for applications such as video surveillance, video composing, video compression, storage and retrieval, and automated target recognition. Video segmentation algorithms involve dissecting the video into scenes based on shot boundaries as well as local objects and events based on spatial shape and regional motions. Many algorithmic approaches to video segmentation have been recently reported, but many lack measures to quantify the success of the segmentation especially in comparison to other algorithms. This paper suggests multiple bench-top measures for evaluating video segmentation. The paper suggests that the measures are most useful when 'truth' data about the video is available such as precise frame-by- frame object shape. When precise 'truth' data is unavailable, this paper suggests using hand-segmented 'truth' data to measure the success of the video segmentation. Thereby, the ability of the video segmentation algorithm to achieve the same quality of segmentation as the human is obtained in the form of a variance in multiple measures. The paper introduces a suite of measures, each scaled from zero to one. A score of one on a particular measure is a perfect score for a singular segmentation measure. Measures are introduced to evaluate the ability of a segmentation algorithm to correctly detect shot boundaries, to correctly determine spatial shape and to correctly determine temporal shape. The usefulness of the measures are demonstrated on a simple segmenter designed to detect and segment a ping pong ball from a table tennis image sequence.

Optical matrix multiplication is generally carried out in the analog domain. In this work, we present a digital domain technique for multiplication using VLSI SLMs and CCD detectors.

In robust tumor recognition engine implementation, it is important to superimpose different types of MR images to verify the adequacy of treatment. Usually, the tumors in time- staggered MR images may vary in shape, format, orientation, angle, translation, scale and by a variety of other distortions. It is already known that various image registration techniques such as Affine transform suffers from lack of speed. Thus, the ability to extract distortion- invariant image features is highly desirable for improved speed and efficiency. We propose to explore distortion- invariant metadata extraction and subsequent classification of tumor in brain MR images.

The projection slice theorem has been used to create synthetic discriminant function (SDF) based matched filters that are capable of discerning rotation and scale distortions. In this paper, we propose to use the projection slice algorithm for invariant face recognition that is capable of accommodating in-plane and out-of-plane 3D distortions. The projection slice algorithm is applied to train images in order to synthesize a composite image to represent each class. The optoelectronic fringe-adjusted joint transform correlator (JTC) technique is then used to correlate the test images with the composite images of each class. The fringe-adjusted JTC technique has been chosen due to its superior performance over alternate JTCs and the feasibility of its implementation in the all- optical domain. Simulation results are furnished to prove the effectiveness of the proposed system.

We present a novel optical integrator with a semiconductor optical amplifier (SOA) and an infinite impulse response fiber optical loop filter in this paper. Adjusting the filter parameters, we can achieve an integrator that can execute integration in a short pulse period. Because the infinite impulse response filter includes a 2 X 2 electro-optical (E/O) switch, the pulse shape after the integration can be varied according to an external driving voltage. According to the calculation result, the gain coefficient of SOA can provide a design flexibility for approaching a real integration.

In this paper, some wavelength routers with various 8 X 8 optical wavelength-switching networks are designed. All of the wavelength routers have three stages architecture. We also analyze the wavelength crosstalk, SNR and BER for various 8 X 8 optical switching networks for adaptive wavelength routing choice. The analysis shows the performance adaptive of routing networks. The 8 X 8 dilated Benes optical switches that adaptive router closed will the best performance among the wavelength routers.

Zernike phase-contrast method is proposed for its application to optical pickup head for the two-layer optical disk. The most attractive feature of this proposed approach is that a very simple architecture can be fabricated for simultaneous readout of both layers with only one objective lens. After giving the basic theoretical analyses of Zernike phase-contrast method, we constructed one feasible system based on this method and discussed the influences caused by the possible phase change of the high order spectrum and the finite aperture. The experimental demonstration of the proposed system is given.

In this paper a generalized look-ahead logic algorithm for number conversion from signed-digit to its complement representation is developed. By properly encoding the signed digits, all the operations are performed by binary logic, and unified logical expressions can be obtained for conversion from modified-signed-digit (MSD) to 2's complement, trinary signed-digit (TSD) to 3's complement, and quaternary signed-digit (QSD) to 4's complement. For optical implementation, a parallel logical array module using electron-trapping device is employed, which is suitable for realizing complex logic functions in the form of sum-of-product. The proposed algorithm and architecture are compatible with a general-purpose optoelectronic computing system.