摘要:

AbstractOptical parallel transmission is an effective technique for various interconnections, e.g., the interface between computer equipment. Monolithically integrated optoelectronic arrays for this purpose are very promising to realize compact, low power‐consuming, highly reliable, and low‐cost systems.In this paper various devices are examined and compared in terms of the forementioned requirements. As the most suitable optical devices, a 12‐channel, 1.3‐μm mesa‐structure planar LED array with high output power at low drive current and a low crosstalk InGaAs pin‐PD array with separated‐unit structure have been developed. Coupled with the GI 62.5 multimode optical fiber, the output power, rise time and fall time of the LED array were ‐16 dB, 2.7 and 1.5 ns, respectively, at 12‐mA drive current.Because of the low‐current operation, the interaction among channels due to heat generation was negligible. A separated‐unit structure was used for PD array to suppress crosstalk. As a result, the capacitance between two channels was as low as 0.05 pF, leading to the measured crosstalk lower than ‐40 dB until hundreds of megahertz 7‐mm thick compact modules with 1.5‐W power consumption have been fabricated and optical parallel transportation of 12‐channel, 150‐Mbit/s/ch for 100‐m distance

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751201

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractWith the purpose of developing a highly efficient guided‐wave optical modulator, an inverted slot line has been proposed for realizing a perfect velocity matching. Modulation experiments were conducted at the 10‐GHz band. Despite its simple structure, the inverted slot line can increase the phase velocity of the modulating wave substantially by changing the spacing between the slot surface and the ground plane, and hence the velocity matching can easily be attained. From the structural limitation of the inverted slot line, the input of the modulating wave from a coaxial cable must rely on the non‐contact excitation.A transition for such a purpose was fabricated first. Next, the propagation characteristics of the inverted slot line were investigated experimentally. It was confirmed that perfect velocity matching can be realized between the optical wave and the modulating wave if the spacing between the slot surface and the ground plane is about 200 μm for 10 GHz and 22 μm for 50 GHz, although certain variations exist, depending on the slot width. An optical modulator was actually built with a Ti:LiNbO3optical waveguide, and the phase modulation operation was confirmed at a wavelength of 633 nm. At the modulating frequency of 9 to 12 GHz, the maximum phase modulation of 2.11 rad was measured with a modulating power of 100 mW. Hence, the possibility of a highly efficient guided‐wave optical modulator was dem

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751202

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA surface acoustic wave convolver composed of ZnO with high piezoelectricity and GaAs with high mobility is thought to be a highly efficient active device, and considerable work and development has been carried out on this device. However, no theoretical analysis which takes into account every parameter such as the dependencies on ZnO film thickness and carriers in GaAs has been carried out.In this paper, the propagation characteristic of the surface acoustic wave in the ZnO/GaAs system was analyzed theoretically, taking into account the semiconductor carrier concentration in order to clarify the dependencies of the convolution efficiency of a ZnO/GaAs convolver on the ZnO film thickness, carrier density, and mobility. In addition, the dependencies of the convolution output on the surface acoustic wave oscillation characteristic in the ZnO/GaAs system and carrier density will be shown.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751203

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA new method is proposed for the numerical analysis of the propagation characteristics of open‐type axially symmetric waveguides by means of the finite element method.First, a novel variational expression suitable for the waveguide analysis is presented which uses electric field components as the trial function. When this variational expression is used in the finite element analysis, no spurious solution is generated.Next, a mapping technique is proposed to apply the finite element method to the entire region of the opentype axially symmetric waveguide. In this method, the entire region of the open‐type axially symmetric waveguide is divided into a finite core region and an infinite cladding region. By means of a coordinate transformation, the cladding region is mapped to a finite region. The finite element method is applied to the finite core and mapped cladding regions and the variational expression is reduced to a generalized eigenvalue problem in which the propagation constant is the eigenvalue. Hence, no repetitive calculation is necessary and the computational effort can be reduced.As practical examples, a step index fiber and a graded index fiber are analyzed numerically and the validity of the proposed method is confir

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751204

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractLiNbO3waveguide quasi‐phase matching (QPM) second‐harmonic generation (SHG) device is promising as a short‐wavelength coherent light source. To realize such device it is important to establish a ferroelectricdomain inversion technique. The authors have found that by heating an LiNbO3crystal for two hours at 1000°C with SiO2cladding of about 0.1 μm thick on the +Zsurface, the domain inversion is induced under the cladding. This inversion method is suitable for device fabrication since uniform domain inversion is induced with good reproducibility under a wide heat‐treatment condition. The dependence of the SHG efficiency on the waveguide size and on the domain inversion cross‐section structure is calculated.A prototype waveguide SHG device, which can compensate for the residual phase mismatch, with domain‐inverted grating formed by this inversion method was demonstrated. An SHG experiment using a CW‐Nd:YAG laser light as the fundamental wave resulted in a high SHG efficiency of about 45‐percent W. It was seen that the domain‐inverted grating formed by the present method is suitable for application

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751205

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractIt is demonstrated theoretically and experimentally that hybrid‐type bistability operations based on the Kerr effect can be obtained in a Mach‐Zehnder interferometer‐type thin‐film optical waveguide made of a polymer thin film doped with nonlinear organic dyes such as disperse orange 3, trans‐β‐carotene and nitroaniline derivatives. It is shown also that the Kerr constants of the dye‐doped polymer thin film can be measured by using the optical control characteristics in this device. The values are 10−14to 10−13m/V2even with dye‐doping of several wt%. Further, an optical‐optical switching operation is possible although a high fee

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751206

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThe high‐speed and highly accurate arithmetic unit is becoming more important. Especially, one factor that determines the system performance is the execution of the multiplication/division, which arises frequently and takes a long computation time. The most appropriate idea in improving the speed is the parallel hardware architecture.Often in the system design, the capacity of the initially designed arithmetic unit becomes insufficient due to the change of specification and the upgrading of the system function after the design making the circuit redesign necessary. Especially, in the case of the divider, such a system redesign is not easy since it cannot be used if the number exceeds the word length. If the number exceeds the operational capacity even by a bit in the divider, it is difficult to cope with the requirement, even if a memory or an external circuit is added. Hence, there is less advantage in fabricating a dedicated integrated circuit (IC) and there are only a few examples of the one‐chip divider.The high‐speed dedicated arithmetic unit includes digital signal processing (DSP) circuitry and a DSP coprocessor, but the division is executed by the software since it is not advantageous to include the divider. This requires a long computation time.From such a viewpoint, this paper proposes an architecture for the parallel divider which can cope with any requirement for the accuracy only by employing several similar dividers. Detailed problems in the expansion of the operational accuracy are discussed, and the proposed divider architecture is described. The one‐chip implementation also is discussed.By this structure, an advantage is produced to prepare the dedicated divider, and the cheap, efficient and high‐speed division can be realized by a relatively small‐scale divider. The proposed divider will be applied widely, not only to the general scientific computations but also to various control systems, signal processing, and computer co

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751207

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractDownscaling methods of electrically erasable programmable ROM (EEPROM) for application‐specific integrated circuit (ASIC) applications based on the double‐poly floating‐gate process were studied. Simple scaling of ASIC and EEPROM modules with the same scaling factor can significantly reduce the time for design and development.Horizontal scaling of the memory cell with unchanged vertical dimensions does not alter the cell performance because the capacitance coupling ratios are kept constant. Vertical scaling, which further reduces the cell size due to less short channel effects, requires the improvement in the tunnel oxide quality. For this purpose, an improved process also was studied in terms of process temperature and phosphorus concentration in polysilicon

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751208

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractA 64 K × 4 Bi‐CMOS ECL self‐timed RAM was developed. It is a register‐register type memory and incorporates register circuitry for input and output buffers. It employs an ECL interface for accommodating high‐speed systems. The input and output ECL registers minimize the set‐up and hold times and the clock access time. Reduction in the cycle time was achieved by adopting a fast, small Bi‐nMOS word driver including a merged bipolar‐pMOS device and by dividing the read data bus into two halves with a main sense amp, which operates as a current‐to‐voltage converter. A hierarchical reference voltage generator was introduced to realize a reliable operation by suppressing a variation in threshold voltages of the ECL input buffers due to wire resistances through the reference voltage wire inside the chip. The cycle time of 5 ns and the clock access time of 2 ns were obtained by the circuit techniques described in the foregoing, implemented on a 0.8‐μm Bi‐CMOS process with three layers of polysilicon

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751209

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY

摘要:

AbstractThis paper describes a solid paper rechargeable battery using an electrolytically polymerized polyaniline film as the electrode and nonaqueous electrolyte gel with high ionic conductivity as the solid polymer electrolyte.A high‐strength fibril polyaniline film with a tensile strength of 5 kgf/cm2was formed by electrolytic polymerization in tetrafluoro‐boric acid. It was found that the film had an excellent oxidation‐reduction characteristic in the solid polymer electrolyte. In addition, by bridging a highly concentrated nonaqueous electrolyte in monomer, the ionic conductivity of the solid polymer electrolyte was comparable with that of liquid electrolyte.Since the solid polymer electrolyte was fabricated using a solution with low viscosity, a solid paper lithium rechargeable battery with a highly efficient discharging property was realized by combining a polyaniline

ISSN:8756-663X    

DOI:10.1002/ecjb.4420751210

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1992

数据来源: WILEY