bluuebunny/crossref_metadata_2025_split huggingface dataset:
Twenty‐five‐inch diagonal high‐contrast color plasma display panels
Authors: Fujii Kozo , Sawai Hideo , Takano Yoshimichi , Sakai Tetsuo 
Published: July 2007

AbstractA 25‐inch diagonal high‐contrast color plasma display panel was fabricated by using thick‐film printing technology. This paper discusses the design and process requirements for making this large‐size plasma display panel.In designing the panel, priming paths were made in the gaps between cathodes and leveling barriers. This resulted in satisfactory discharge characteristics over the entire area of the panel. For the printing process, an improved printer and optimized printing conditions were used. the durability of the print screen was examined under the printing conditions.To identify the cause of uneven luminance within the panel, the authors examined the effects of the distri bution of various parameters on the intenial surface of the panel and found that the precision of the positioning of cell formation elements is the most important factor in prevention of unevenness of luminance.
Design and simulation of optical integrated circuits
Authors: Koshiba Masanori 
Published: July 2007

AbstractThis paper describes the basic items needed for design and simulation of optical integrated circuits and analysis tools for optical waveguides. Because the finite element method and beam propagation method are emphasized, the scalar wave approximation (which has been extensively used) is used in the discussion. In addition, using examples of analyses on various optical integrated circuits, the design and simulation technologies for optical integrated circuits will be introduced.
A quasiphase‐matched waveguide for the blue second‐harmonic generation
Authors: Yamada Masahiro , Nada Naoji , Yamaguchi Takeshi , Saitoh Masaki , Watanabes Kenjiro 
Published: July 2007

AbstractAn optical waveguide second‐harmonic genration (SHG) device in a quasiphase matched (QPM) system that obtains blue laser light from an infrared laser diode has shown promise. to obtain sufficient output power, it is necessary to understand how a high‐frequency conversion efficiency is attained in the SHG device. the technology for periodic inversion of the sign of the nonlinear optical constant is the key to full development of the QPM system. Most of the nonlinear optical crystals used for optical waveguide SHG devices in the QPM system are ferroelectric. In such crystals, self‐generated polarization is inverted so that the inversion of the sign of the nonlinear optical constant is carried out by polarization inversion. the authors have succeeded in forming a periodic inversion mechanism extremely ideal to the QPM by applying an external electric field in the device using lithium niobate. A conversion efficiency reaching 600 percent/W · cm2 has been realized.Various polarization inversion methods are introduced herein. the QPM system optical waveguide SHG device is explained in which the polarization periodic inversion mechanism is formed by the applied electric field on the lithium niobate.
Lossless and low crosstalk 4 × 4 optical switch array
Authors: Kirihara Toshio , Ogawa Mari , Inoue Hiroaki , Ishida Koji 
Published: July 2007

AbstractThe optical switch array is a key device for realizing photonic switching systems. A lossless and low crosstalk switch is the most desirable component of large‐scale switching systems which have more than 100 input/output ports. to realize such a switch monolithically, a carrier‐injection‐type optical single‐slip structure (S3) switch with traveling‐wave amplifier (COSTA) have been proposed. to realize the COSTA, a carrier‐injection‐type optical switch and an optical amplifier that are suitable for integration have been developed. First, a carrier‐injection‐type optical switch where the PN junction was formed by crystal growth was fabricated. It was confirmed that the characteristics of the device do not deteriorate during heating, which makes it suitable for integration. Next, the structure of an optical amplifier which can be integrated into the optical waveguide using the reactive ion etching (RIE) process was investigated. an optical amplifier that was integrated into a straight optical waveguide was fabricated, and it was confirmed that this amplifier could produce enough gain (internal gain of 25 dB) to compensate for the loss in the optical switch. Using these two basic techniques, a 4 × 4 COSTA was fabricated. With this 4 × 4 COSTA, fiber‐to‐fiber lossless (maximum gain of 5 dB) and extremely low crosstalk characteristics (ON‐OFF ratio of 54 dB) were demonstrated.
Semiconductor photonic integrated devices
Authors: Tada Kunio , Nakano Yoshiaki 
Published: July 2007

AbstractSemiconductor materials are suitable for monolithic photonic integrated circuits since they can realize almost all the necessary photonic functions such as light emission, light amplifications, light detection, light modulation/switching and optical waveguiding. Additionally, since the figure of merit of various physical effects used to realize the foregoing functions is large and since it is easy to arrange the spatial region to generate these effects into compact and convenient shape, it is advantageous for small size and high performance.The research and development of photonic integrated circuits utilizing semiconductors has an accumulation of history, knowledge, and technology, already spanning a quarter of a century. Although it has required a longer time before it becomes practical than the electronic integrated circuits, it has shown rapid progress since the end of 1980's. This is attributed to the combination of the driving force from the needs point of view based on the advances in semiconductor laser technology, introduction, and spreading of quantum well structures and evolution of processing technology such as epitaxial growth methods and the strong demand from the needs point of view toward all optical telecommunication networks where not only trunk lines but also switching nodes and subscriber lines use an optical wave.This paper reviews the present status of photonic devices and circuits obtained by monolithic integration of semiconductor element devices by classifying them into light emitters, optical switches, and combiners/splitters. Finally, the necessity of semiconductor integrated photonic systems is set forth toward the future.
Reproduction of optical reflection‐intensity‐distribution using multimode laser coherence
Authors: Tanno Naohiro , Ichimura Tsutomu 
Published: July 2007

AbstractA new reflectometry method is proposed which enables measurements of light‐reflection‐distributions with spatial resolutions below tens of micrometers. the method can be applied to the detection of the damaged point of optical fibers, optical integrated circuits (ICs), reproduction of optical waveguide three‐dimensional memories, etc. By consideration of the coherency of a multimode laser, it becomes possible to construct the reflectometer without the need for frequency scanning of the optical source and movable parts.The interference light from the Michelson interferometer or from the interfaces of the multilayer object are analyzed (by the spectrometer) and square detected to obtain the interferospectrum of the interference light. Using the property that the interferospectrum is the duplicate of the reflection distribution, the Fourier inverse transform of the reflection distribution is carried out and the “spatialgram” is reproduced. the spatial resolution is determined by the inverse of the spectrumwidth of all modes. Therefore, even if a common multimode laser diode, available on the market with all‐mode spectrum‐width of 10 nm is used, the high resolution of about 34 μm can easily be achieved. Numerical results of the theoretical analysis of reflections, in the frequency domain, also are presented.
Analysis of dielectric optical waveguides using the nonorthogonal finite‐difference time‐domain (FD‐TD) method
Authors: Araki Makoto , Kashiwa Tatsuya , Tagashira Hiroaki 
Published: July 2007

AbstractResearch and development of optical circuit elements become important as the degree of integration of the optical circuit is advanced. Since the optical devices are integrated and become more complex and as optical circuit elements with high index difference begin to appear, the conditions of the weakly guided wave and of the reflectionless wave no longer hold rigorously. Hence, rigorous numerical analysis is needed.One of the analysis methods for the optical circuit elements is the finite‐difference time‐domain (FD‐TD) method. Recently, as a generalization of the FD‐TD method, the nonorthogonal FD‐TD method has been proposed. In this paper, the optical circuit elements are analyzed by means of the nonorthogonal FD‐TD method which is capable of analyzing optical circuit devices with various shapes. First, tapered waveguides are analyzed. the results are compared with those by the beam propagation method (BPM) and the characteristics with respect to the tapered angle are derived. Next, a directional coupler with a high refractive index difference is analyzed. the effectiveness of the present method for the coupling characteristics is presented.
A thermal characteristic stabilization method for an optical voltage sensor using optical rotary power
Authors: Ohtsuka Masao , Furuta Takashi , Shimomura Teruo 
Published: July 2007

AbstractThe longitudinal type optical voltage sensor made of Bi12GeO20 (BGO) crystal is often used in practical applications because it has a large electrooptical coefficient γ41, temperature stability, and no natural birefringence. Since this electrooptic crystal has large optical rotary power, sensitivity degrades when the crystal is thick. However, if optical rotary power is utilized, it is possible to control arbitrarily the temperature coefficient × of the sensor sensitivity. It was proved theoretically that the temperature coefficient of sensor sensitivity was dependent on the temperature coefficient β of the half wavelength voltage Vπ, the temperature coefficient β of the optical rotary angle θ0 the crystal thickness d (optical rotary angle θ0), and the cut angle θ. In addition, in order to verify the theory, × was determined by evaluating a sensor at temperatures ranging from ‐20 to 80°C. As a result, it was found that the value of × varied arbitrarily from ‐7.6 × 10−4 to + 4.0 × 10−3 (1/°C).
Analysis of optimum behavior for peltier cooling system
Authors: Ogawa Yoshihiko 
Published: July 2007

AbstractThe optimum operating condition of a Peltier cooling system was accurately derived by using a thermoelectric differential equation developed by the author. Using the obtained result, the influences of the Peltier device current and length on the cooling characteristic were analyzed. One of the most serious drawbacks of the Peltier cooling system is the low value of COP; an increase of COP is the most important issue in designing a cooling system. the optimum operating condition described herein is that operation limit which provides maximum COP. When a large temperature difference is required, multiple stages of Peltier devices connected in cascade are used. Therefore, theoretical analysis for cascade structure used arbitrary N stages.
Uniform microdroplet formation of polymer‐dispersed liquid crystal using undercoating films
Authors: Fujikake Hideo , Takizawa Kuniharu , Kikuchi Hiroshi , Fujii Takanori , Kawakita Masahiro 
Published: July 2007

AbstractIt is found that liquid crystal microdroplets become uniform and their sizes are reduced if the substrates are coated with some undercoating film before forming polymer‐dispersed liquid crystal using the photopolymerization‐induced phase separation method.In this study, polyvinylalcohol was used for the undercoating film because it has good wetting property to the liquid‐crystal material, resulting in suppression of nonuniform nucleation and growth of the microdroplets. In the polymer‐dispersed liquid crystal formed under ultraviolet (UV) irradiation with 10 mW/om2, the diameter of the liquid‐crystal droplets varied in a range up to approximately 6 μm without using an undercoating film while the variation of the droplet diameters became less than 2 μm when the undercoating film was used. As a result, the threshold characteristic in the electrooptic property, response time, spatial resolution, and film uniformity were improved drastically by using the undercoating film. By using the polymer‐dispersed liquid crystal formed in this new method, a high limiting resolution (as high as 128 1p/mm) was achieved. the polymer‐dispersed liquid crystal formed in this way is expected to be used for projection displays with high resolution and high brightness.
The oxidation process and dissipation factor of Al/Ta/Hf multilayered anodized thin‐film capacitors
Authors: Dobashi Tsuyoshi , Umezawa Toshiji , Sasaki Katsutaka , Noya Atsushi 
Published: July 2007

AbstractIt is known that the anodic oxidation of Hf proceeds by the diffusion of anions into Hf thin film and is affected by the other overlayered films existing on Hf in multilayered anodized thin‐film capacitors. to characterize multilayered thin oxide film structures necessary for the fabrication of high‐quality capacitors, a correlation between dissipation factor and oxidation process has been investigated as a function of anodization voltage and thinfilm thicknesses of Al/Ta/Hf and Ta/Al/Hf multilayers.The results indicate that thin‐film capacitors with low dissipation factor can be obtained by anodizing Al/Ta/Hf thin films so long as their original multilayered structures are maintained during anodization and the Ta intermediate layer acts as a transport medium of oxygen ions for the bottom Hf layer. With increasing anodization voltage, Ta ions migrate toward the surface of the multilayer, which alters the original multilayered structure and contributes to higher dissipation factor.When the intermediate layer is Al such as in the case of Ta/Al/Hf multilayer capacitors, the flow of oxygen ions to the bottom Hf layer is restricted during anodization by the formation of an oxidized Al layer and this makes the dissipation factor higher. It has been concluded that in order to fabricate thin‐film capacitors with low dissipation factor, it is vital to have the presence of an intermediate layer such as Ta which has a lower heat of formation for oxidation than Hf.
Densely spaced optical FDM‐homodyne detection systems using optical fitters
Authors: Yonenaga Kazushige , Norimatsu Seiji 
Published: July 2007

AbstractThis paper investigates the effect of channel‐to‐channel interference in optical frequency division multiplexing (FDM)‐homodyne detection systems that use optical filters for densely‐spaced optical FDM systems. Power penalties at BER = 10−9 for double‐sideband (DSB), single‐sideband (SSB), and vestigial‐sideband (VSB) signals were evaluated by approximating the channel‐to‐channel interference as Gaussian noise. the authors investigated four cases: where no optical filter was used; where an optical channel selection filter was used at the receiver, where an optical filter suppressing spectrum broadening was used for each channel before multiplexing at the transmitter; and where both of these filters were used. It has been shown that using an optical filter before multiplexing is effective for reducing channel spacing. the optical filterings are effective especially for SSB and VSB signals. Extremely densely‐spaced multiplexing with a channel spacing of less than twice the bit rate can be achieved with a power penalty of less than 0.1 dB.
Analysis of current runaway in a DC‐DC converter with current‐injected control
Authors: Matsuo Hirofumi , Kurokawa Fujio , Imamura Ken , Asano Mutsuyoshi , Koga Takashi 
Published: July 2007

AbstractThe purpose of this paper is to examine the occurrence mechanism of the current runaway phenomenon in the overcurrent limited mode of the dc‐dc converter with current injected control. Taking into account the time delay in the turn‐off instant of the switch, which is due to the dead time and the time constant of the control circuit and the dead time of the switch, this phenomenon is analyzed.As a result, it is clarified that there exist two operation modes in the overcurrent limited mode of the dc‐dc converter with current‐injected control; in one mode, the current limiting characteristics are affected by only the dead time of the control circuit and the switch and, in the other one, both the dead time and the time constant of the control circuit and the dead time of the switch have an effect. the current runaway phenomenon occurs in the latter mode. the boundary condition of these two modes is defined. Consequently, the design criterion is presented to prevent the current runaway phenomenon.
Stability against temperature and environment for ground‐resistance reducing material using water‐absorbent polymer
Authors: Yamane Hiroshi , Ideguchi Tsuyoshi , Tokuda Masamitsu 
Published: July 2007

AbstractAs the number of communication facilities increases, the number of groundings installed in such stations also increases. It is difficult to achieve the specified ground‐resistance value in such high ground‐resistance regions as volcanic ashes, sands, and rocks. In this paper, as a ground‐resistance reducing material, a waterabsorbent material solidified by plastic hardener is treated. Its stability in an air and water environment is described.As a water‐absorbing material, anhydrous maleic acid polymers are selected. It is found that this material maintains the characteristics for about 10 years if the performance degradation of 20 percent is allowed and about 20 years if 50 percent is allowed. For the reducing material made of an absorbing material solidified by epoxy, it is found from the environmental degradation characteristics by changing the temperature in air that the dry condition can be allowed for about one year during which the ground resistance can maintain its initial value if rain falls and is sufficiently stable. Further, from the environmental degradation characteristics in water, it is found that the ground resistance maintains the initial value and the compression strength is not degraded unless the temperature is more than 70°C. Hence, the stability is sufficient even in water.
Optical neurochip for image processing
Authors: Nitta Yoshikazu , Ohta Jun , Tai Shuichi , Kyuma Kazuo 
Published: July 2007

AbstractThis paper proposes a method to realize a highspeed processing of image data utilizing the analog memory function of the optical neurochip. The result of experiment also is presented. The features of the proposed method are that the image data can directly be processed in the two‐dimensional form and a large‐scale problem can be processed with a high speed by utilizing the spatial parallelism of the light.In this paper, it is shown first that the variable sensitivity photodetector, which is the basic element of the system, can function as the optical analog memory, where the value proportional to the product of the input light intensity and the control voltage is stored hi the element as the light detection sensitivity and the stored value can be read by the optical signal. Then the application of the optical analog memory function to the image processing is considered. The optical neurochip is constructed by integrating the variable sensitivity photo‐detector in a two‐dimensional array, and it is shown that the difference of two input images can be calculated. The function is realized by selecting the polarity of the control voltage in inputting the pattern.Lastly, the image difference function is applied in the experiment for the selective detection of the moving object where the dynamic image is used as the input. In other words, the light irradiated from the moving object is used as the input pattern; and it is shown experimentally that the trajectory of the moving object is detected but the signal is not detected when the object is still.
Vertical photonics: A new way to integrate photonic devices into optical fibers
Authors: Kawakami Shojiro , Hanaizumi Osamu 
Published: July 2007

AbstractVertical photonics is the technique of direct integration of optical functional devices or their integration into optical fibers. In optical fiber systems, it is usually very difficult to match the modes of optical fibers to those of minute devices or to adjust their positions accurately. To solve such connection problems, the expanded core fibers are used, the aperture of the device is enlarged, and the optical path is shortened. In this paper, the concept of vertical photonics is discussed and the present status of the basic components (wavelength filters, polarizers, polarization splitters, etc.) and optical devices (isolators, optical switches, wavelength tunable filters, amplifiers, etc.) is reviewed.
Advanced optical packaging technology for practical integrated photonic modules
Authors: Nakajima Hirochika 
Published: July 2007

AbstractFor optical communication technology, which has been pushing for higher speed and larger capacity in the transmission trunk lines, the urgent tasks are not only improvements in performance but also the expansion of applicable areas by introducing new functions and moving into new phases.For optical fibers to be applicable in access net, subscriber loop, intrastation transmission systems, and interprocessor connections, the realization of optical links that are easy to use, easy to fabricate; and inexpensive, is strongly demanded. Also, the appearance of optical nodes everywhere in the broad bandwidth network that will be the backbone of the multimedia society would not be too far off. Research on integrated optical devices and circuits that have new structures for waveguide‐type devices, array components, or two‐dimensional devices, is continuing to progress to meet these demands.To mount these devices and circuits compactly and inexpensively into packages and modules, innovative packaging techniques have to be developed correspondingly. From this viewpoint, this paper reviews optical packaging technology, which holds the key to the realization of integrated photonics.
Iterative finite difference beam propagation method analysis of nonlinear optical waveguide excitation problem
Authors: Yokota Hirohisa , Hira Masafumi , Kurazono Sadao 
Published: July 2007

AbstractThe beam propagation method (BPM), used widely for analyzing optical waveguides and optical circuits, is also being applied to devices that include nonlinear materials. However, in the analysis of nonlinear optical devices using the conventional BPM, in many cases it is assumed that the field intensity distribution does not change within the step length in propagation direction. Therefore, for accurate calculation, the step size in the propagation direction must be extremely small, which results in long calculation times.Therefore, this paper proposes and formulates a numerical method where the solution is forced to converge by the iterative calculation of a difference equation over each propagation step of the Crank‐Nicolson BPM method. Using this method, first, we analyzed the case where the fundamental TE mode propagates in the dielectric slab waveguide that has a Kerr‐like nonlinear cladding. By calculating the emission angle of the optical beam into the cladding, the present method is compared with the conventional method. After it is demonstrated that this present method is effective, the dependency of the optical beam emission angle for the incident power is shown. Furthermore, the effect of the beamwidth on the excitation is analyzed in the case where a nonlinear stationary wave is excited by a Gaussian beam and the interesting results are proved.