A directly modulated LED or SLD (super luminescent diode) is attractive for low-cost lightwave systems such as access networks. This letter experimentally studies a directly modulated SLD followed by a gain-saturated semiconductor optical amplifier (SOA), and shows that the modulation rate is expanded in effect by the use of the gain-saturated SOA. This results from the shortened response time of the SLD due to the ASE light from the SOA and a level-equalizing effect in the gain-saturated SOA.

There is increasing interest using CMOS circuits for highly integrated high frequency wireless telecommunications systems. This paper reviews recent works in transceiver architectures, circuits and devices technology for CMOS RFIC application. A number of practical problems those must be resolved in CMOS RFIC design are also discussed.

Non-stationary glint noise is often observed in a radar tracking system. The distribution of glint noise is non-Gaussian and heavy-tailed. Conventional recursive identification algorithms use the stochastic approximation (SA) method. However, the SA method converges slowly and is invalid for non-stationary noise. This paper proposes an adaptive algorithm, which uses the stochastic gradient descent (SGD) method, to overcome these problems. The SGD method retains the simple structure of the SA method and is suitable for real-world implementation. Convergence behavior of the SGD method is analyzed and closed-form expressions for sufficient step size bounds are derived. Since noise data are usually not available in practice, we then propose a noise extraction scheme. Combining the SGD method, we can perform on-line adaptive noise identification directly from radar measurements. Simulation results show that the performance of the SGD method is comparable to that of the maximum-likelihood (ML) method. Also, the noise extraction scheme is effective that the identification results from the radar measurements are close to those from pure glint noise data.

An approximate formula is proposed for the equivalent susceptance of a circular iris in a parallel plate waveguide when the TEM mode cylindrical wave is incident from the center of the iris. Schwinger's variational method for a linear iris is generalized to the cylindrical case, and an approximate closed form formula is obtained which recovers the result of the linear iris when the radius of the circular iris is sufficiently larger than the wavelength. For verification of the formula, an exact integral equation is formulated and solved numerically by Galerkin's method. A comparison between them shows good agreement.

For the realization of low-voltage full-color FEDs, requirements for phosphor for the FED are proposed. Especially, the influence of released gases or substances from phosphors on the field emission within the FED was made clear. It was clarified that the analysis of F-N plots of the V-I curve of field emission characteristics was helpful to know the interaction of field emission and phosphors. In the experiment, we first obtained the depth from the phosphor surface of the low voltage electron excitation in case of ZnGa2O4, where the region available for cathodoluminescence at the anode voltage of 400 V is about 63 nm deep from the surface. The characteristic of the 12.4 cm-320(trio)240 pixels low-voltage full-color FED is reported. The luminance of 154 cd/m2 was attained at the anode voltage of 400 V and the duty factor of 1/241. Supported by the high potential of the FED as a flat panel, each problem shall be steadily solved to secure the firm stand as a new full color flat display in new applications.

This paper describes design techniques for suppressing crosstalk in an optical transceiver module using PLC-hybrid-integration technologies and for achieving burst-mode operation with high sensitivity and wide dynamic range using CMOS-IC technologies. An arrangement that reduces the electrical crosstalk to less than -100 dB was designed using three-dimensional electromagnetic field analysis. The configurations of a newly developed instantaneous-response CMOS LD driver circuit is also described and instantaneous-response CMOS receiver circuit techniques are reviewed. With these techniques, we have succeeded in building optical transceiver modules for ATM-PON systems using PLC-hybrid-integration and inexpensive standard CMOS-IC fabrication processes. Under full-duplex operation at 156 Mb/s, fabricated transceiver modules showed receiver sensitivity of better than -34 dBm and dynamic range of over 28 dB, which satisfy both the class-B and class-C specifications recommended by ITU-T (International Telecommunication Union-Telecommunication standardization sector) G983.1 for the optical transceiver module for an ONU (optical network unit).

A novel combinatorial optimization algorithm called 2-stage discrete optimization method (2DOM) is proposed for the largest common subgraph problem (LCSP) in this paper. Given two graphs G=(V1, E1) and H=(V2, E2), the goal of LCSP is to find a subgraph G'=(V1', E1') of G and a subgraph H'=(V2', E2') of H such that G' and H' are not only isomorphic to each other but also their number of edges is maximized. The two graphs G' and H' are isomorphic when |V1'|=|V2'| and |E1'|=|E2'|, and there exists one-to-one vertex correspondence f: V1' V2' such that {u, v} E1' if and only if{f(u), f(v)} E2'. LCSP is known to be NP-complete in general. The 2DOM consists of a construction stage and a refinement stage to achieve the high solution quality and the short computation time for large size difficult combinatorial optimization problems. The construction stage creates a feasible initial solution with considerable quality, based on a greedy heuristic method. The refinement stage improves it keeping the feasibility, based on a random discrete descent method. The performance is evaluated by solving two types of randomly generated 1200 LCSP instances with a maximum of 500 vertices for G and 1000 vertices for H. The simulation result shows the superiority of 2DOM to the simulated annealing in terms of the solution quality and the computation time.

This paper describes design techniques for suppressing crosstalk in an optical transceiver module using PLC-hybrid-integration technologies and for achieving burst-mode operation with high sensitivity and wide dynamic range using CMOS-IC technologies. An arrangement that reduces the electrical crosstalk to less than -100 dB was designed using three-dimensional electromagnetic field analysis. The configurations of a newly developed instantaneous-response CMOS LD driver circuit is also described and instantaneous-response CMOS receiver circuit techniques are reviewed. With these techniques, we have succeeded in building optical transceiver modules for ATM-PON systems using PLC-hybrid-integration and inexpensive standard CMOS-IC fabrication processes. Under full-duplex operation at 156 Mb/s, fabricated transceiver modules showed receiver sensitivity of better than -34 dBm and dynamic range of over 28 dB, which satisfy both the class-B and class-C specifications recommended by ITU-T (International Telecommunication Union-Telecommunication standardization sector) G983.1 for the optical transceiver module for an ONU (optical network unit).

We developed an optical transceiver diode (TRAD) module for bi-directional time-compression-multiplexing (TCM) transmission systems. A wavelength-insensitive structure as a receiver and a low-capacitance configuration in the module provide a high sensitivity. Stable switching of 156 Mbit/s NRZ burst signals between the transmitter and receiver modes is achieved. In addition, it is shown that optical module cost can be further reduced by using passive alignment on a Si bench.

We developed an optical transceiver diode (TRAD) module for bi-directional time-compression-multiplexing (TCM) transmission systems. A wavelength-insensitive structure as a receiver and a low-capacitance configuration in the module provide a high sensitivity. Stable switching of 156 Mbit/s NRZ burst signals between the transmitter and receiver modes is achieved. In addition, it is shown that optical module cost can be further reduced by using passive alignment on a Si bench.

Recently, Kundur and Hatzinakos showed that a linear restoration filter designed by using the almost obvious a priori knowledge on the original image, such as (i) nonnegativity of the true image and (ii) the smallest rectangle encompassing the original object, can realize a remarkable performance for a blind image deconvolution problem. In this paper, we propose a new set-theoretic blind image deconvolution scheme based on a recently developed convex projection technique called Hybrid Steepest Descent Method (HSDM), where some partial information can be utilized set-theoretically by parallel projections onto convex sets while the others are incorporated in a cost function to be minimized by a steepest descent method. Numerical comparisons with the standard set-theoretic scheme based on POCS illustrate the effectiveness of the proposed scheme.

The recently proposed modified PML (MPML) absorbing boundary condition is extended to three dimensions. The performance of the MPML is investigated by FDTD simulation of a typical microstrip line and a rectangular waveguide. The dominant and higher order modes of the microstrip line and the waveguide are excited separately in the computation. In all of the cases of excitation, the reflection properties of the MPML boundaries are examined for the side walls and the end walls, respectively. Various values of the permittivity and permeability of the MPML medium are tested in the computation, and the variation behavior of reflection from the MPML boundaries is examined. The numerical results reveal that by choosing appropriate values of the permittivity and permeability of the MPML, we can realize efficient absorption of both evanescent waves and propagating waves over a wide frequency band.

Full-wave FD-TD analysis has been carried out for coaxial probes inserted into waveguides. Both single and symmetrically placed paired coaxial probe structures have been discussed and we have revealed the relation between equivalent circuit parameters and structural parameters of the coaxial probes including cases for large diameter and extension length, which is useful for practical waveguide circuit design. The equivalent circuit parameters calculated from the scattering parameters agreed well with corresponding measured data. From the calculated field in a waveguide, field concentration at sharp edges of probe sole or base, which ought to be taken into account for high power application design has been also discussed. Besides, amplitudes of higher order modes in waveguides excited by coaxial probes or pairs of coaxial probes has been calculated so as to estimate the range beyond which higher order modes decay sufficiently. This estimation is necessary for simple and easy design of probe using circuit theory.

Gd2O2S:Tb phosphor thin films have been prepared using the simple technique of electron beam evaporation for large area display applications. The photoluminescence and excitation spectra measurement of Gd2O2S:Tb phosphor thin films suggest that Tb3+ is incorporated into the Gd2O2S lattice at gadolinium sites. Relatively efficient electroluminescence is observed from a ZnS/Gd2O2S:Tb/ZnS sandwich cell.

A 14. 4-in. diagonal EL display with 640128 pixels has been developed in red/green multicolor structures by using a new phosphor layer consisting of Zn1-xMgxS:Mn and ZnS:Mn. The display is designed for 240 Hz-frame rate, enabling the luminance to be improved by a factor of two. In addition, the contrast ratio is strongly enhanced by optimizing the black background structure and color filters. Improved characteristics make it possible for the EL panel to meet the requirements for the public information display taking advantages of high-reliability, crisp image and wide-viewing angle. Furthermore, the possibility of full-color EL displays will be described on the basis of "color by white" approach.

We demonstrate a very simple and compact optical transceiver diode module using a passive alignment on a silicon bench with a V-groove. The excess loss caused by the passive alignment of an optical transceiver diode and a flat-end optical fiber is only 0. 6 dB. A high coupling efficiency of -4. 3 dB is obtained. This results in a high responsivity with a wavelength- and polarization-independence of 0. 5 dB over a 70 nm wavelength range and in good laser performance.

Macroscopic method for quantization of the evanescent fields brought about by total reflection is presented. Here, a semi-infinite space is assumed to be filled with a transparent dispersive dielectric with dielectric constant ε(ω) to the left of the plane z = 0, and be empty to the right of the plane. The wave is assumed to be incident from the left, and so the whole field is composed of the triplet of incident, reflected, and transmitted waves labeled by a continuous wave vector index. The transmitted wave in free space may be evanescent. The triplet is shown exactly without using slowly varying field approximation in dispersive medium to form orthogonal mode for different wave vectors, which provides the basis for the quantization of the triplet with taken into account of medium dispersion. The exact orthogonal relation reduces to the well known one if the dielectric is nondispersive, ε/ω = 0. By using the field expansion in terms of the orthogonal triplet modes, the total field energy is found to be the sum of the energies of independent harmonic oscillators. A discussion is also made on the wave momentum of evanescent field.

In order to improve the running durability of organic electroluminescent devices (OELDs), the doping sites of molecular OELDs were optimized, and the frequency responses of the optimized devices were examined for Mg-In/bis (10-hydroxybenzo[h]quinolinate) beryllium (BeBq2)/N, N'-diphenyl-N, N'-(3-methylphenyl)-1, 1'-biphenyl-4, 4'-diamine (TPD)/4, 4', 4"-tris (3-methylphenylphenylamino) triphenylamine (MTDATA)/ITO. The TPD hole transport layer was the optimum doping site for 5, 6, 11, 12-tetraphenylnaphthacene (rubrene) dopant, and a very high efficiency of 13 cd/A at 0. 13 kcd/m2 was obtained for yellow emission. Half-decay times under a constant direct current density of 1. 0 mA/cm2 from an initial luminance of 0. 13 kcd/m2 extended to longer than 26,000 hours. The luminance of the optimized device decreases lineally with respect to the logarithm of the frequency as the frequency increases in the range from 1 kHz to 0. 3 MHz when a square wave with a duty ratio of 50% and a maximum voltage of 5.0 V is applied. A new driving method involving frequency modulation is proposed. This may offer accurate control of pixel luminance, and enable simple driving circuits adapted to highly integrated digital LSI chips, or the concept of system on glass.

We propose a set of new algorithms for linear programming. These algorithms are derived by accelerating the method of averaged convex projections for linear inequalities. We provide strict proofs for the convergence of our algorithms. The algorithms are so simple that they can be calculated by super-parallel processing. To this effect, we propose networks for implementing the algorithms. Furthermore, we provide illustrative examples to demonstrate the capability of our algorithms.

A multimedia coding standard, MPEG4 has frozen its Committee Draft (CD) as the MPEG4 version 1 CD, last October. It defines Audio-Visual (AV) coding Algorithms and their System Multiplex/Composition formats. Founding on Object-base concept, Video part adopts Shape Coding technology in addition to conventional Texture Coding skills. Audio part consists of voice coding tools (HVXC and CELP core) and audio coding tools (HILN and MPEG2 AAC or Twin VQ). Error resilience technologies and Synthetic and Natural Hybrid Coding (SNHC) technologies are the MPEG4 specific features. System part defines flexible Multiplexing of audio-visual bitstreams and Scene Composition for user-interactive re-construction of the scenes at decoder side. The version 1 standardization will be finalized in 1998, with some possible minute changes. The expected application areas are real-time communication, mobile multimedia, internet/intranet accessing, broadcasting, storage media, surveillance, and so on.