摘要:

AbstractA spatial light modulator GaAs‐pin/ferroelectric liquid crystal spatial light modulator (GaAs‐pin/FLC‐SLM) was developed in which a GaAs photodiode is used as a photodetector, and a ferroelectric liquid crystal is used as a modulator. In the present device, write‐in with visible light and a transmission‐type readout at infrared are possible. Other characteristics of this device include a high‐speed operation due to the use of a ferroelectric liquid‐crystal and no need for erasing light due to the use of a pin diode.In this paper, the configuration of the SLM is presented and the operating principle is explained by means of an operation model. Next, experimental examples as a switching device are described. Also, several examples of the system applications are presented.The first example is a self‐routing crossbar switch. In this switch, the 1.3‐μm signal light is switched by providing a header at a different wavelength to a connected output port. the present SLM is used as an optical switch section. the experimental results of the present switch with 2 × 2 ports are reported.The second example of the system application is an optical parallel processor which is based on the accumulative threshold characteristic of the present SLM. By means of this characteristic, logic operation is possible for time series parallel optical signals. It is presented that the sequential operation system can be constructed in a much simpler configuration. the experimental results for configuration of the

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770101

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

年代:1994

数据来源: WILEY

摘要:

AbstractFor the design of devices using the quantum effect, it is necessary to know the wavefunction of the electrons and holes in the quantum well and multiple barrier structures as well as the characteristic energy levels and resonance levels. It is necessary further to manipulate the potential structures to synthesize a desired phenomenon. to attain these objectives, applications of circuit theory to the analysis and design of quantum effect phenomena have been attempted.In this paper, it is shown that the 2 × 2 interface matrix representing the continuity of the wavefunction and the boundary condition on the wavefunction accompanied by the T‐Xmixing are expressed in terms of the lossless two port and four port, respectively. By means of this procedure, it is now possible to carry out a circuit‐oriented treatment of the behaviors of the electrons and holes in the case of superlattices other than GaAs systems requiring the interface matrix and the case where mixing between the minimum points of the conduction band in GaAs/AlxGal‐xAs for which no circuit treatment was previously possible. They can now be analyzed systematically with the circuit functions and circuit matrices of the equivalent circuit without special boundary conditions. Also, by means of the proposed circuit representation, analysis examples are presented for the tunneling phenomena in these potential stru

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770102

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

年代:1994

数据来源: WILEY

摘要:

AbstractMultilayered monolithic microwave integrated circuits (MMIC) have been proposed with a view to reducing the size and increasing the degree of integration of the MMIC. It has been demonstrated that new circuit configurations can be realized and the design capability can be improved. By the use of a multilayered MMIC, the circuit can be laminated so that the circuit size can be made smaller. However, since the circuit is laminated, qualitative evaluation of the crosstalks between the upper and lower transmission lines becomes important. Most of the previous analyses on the microstrip line crossover focused on the case where the two lines cross orthogonally.In this research, the finite‐difference time‐domain (FD‐TD) method applicable to an arbitrary coordinate system is used for the analysis of the crosstalk when two transmission lines cross at an arbitrary angle.First, the FD‐TD method that can be applied to an arbitrary coordinate system is summarized. Next, it is confirmed that the results of the present analysis for a single microstrip line do not depend on the mesh shape and that the present analysis results agree with those by other methods for a microstrip bend with an arbitrary angle. Finally, a three‐dimensional crossover of micro‐strip lines with an arbitrary angle is analyzed. the normalized frequency characteristics, cross‐angle dependence, and the interdistance dependence of thesparameters

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770103

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

年代:1994

数据来源: WILEY

摘要:

AbstractAn optical bistable device can be useful not only for optical memory but also for optical sensing by using its binary signal process characteristics. In this case, if a nonlinear Faraday medium is used in the optical bistable device, some interesting features can be obtained as already shown by the present author. Those unique characteristics are that, by controlling the polarization direction by an external magnetic field, a multiple interference can also be controlled not only by the phase associated with an optical path variation but also the polarization direction.This paper describes a theoretical analysis of the fluctuation of transmission and reflection as a function of an absorption in a medium besides the incident intensity reduction and discusses the bistability characteristics and the threshold values against the parameters. It is shown that the control of the bistable function, the realization of a low threshold value, and the increase of a discontinuous power variation ratio (= optical intensity ratio betweenonandoffin the binary signal process) at the threshold value are accomplished as the result of the introduction of the external magnetic field control method. Therefore, it can be concluded that a Faraday medium is very useful for an optical bistable device.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770104

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

年代:1994

数据来源: WILEY

摘要:

AbstractA rectangular waveguide was formed with ceramics having a high relative permittivity of 93. This waveguide is divided into two in theE‐plane. This structure was used for the design and fabrication of a bandpass filter of small size and light weight which can be surface mounted. Inductive strips are formed on theE‐plane so that the center frequency of the one‐half wavelength resonator and the coupling coefficient between the resonators are adjusted. Further, by choosing a structure in which the filter is connected directly from a microstrip line, the structure is miniaturized.In the design, first the dimension dependence of the characteristic values of the composite resonators, e.g., the center frequency and the coupling coefficient, was found experimentally. Then a general filter theory was applied. Further, the characteristic values of the resonator were studied theoretically so that the dimension dependence can be explained qualitat

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770105

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

年代:1994

数据来源: WILEY

摘要:

AbstractA superconducting weak link device using InAs/(AlGa)Sb heterostructure has been fabricated, and its electrical property has been characterized for applications to high‐performance superconducting transistors. the semiconductor layers consist of InAs/(AlGa)Sb heterostructure with high mobility and high electron density; the superconducting electrodes consist of Pb alloy superconducting thin films.InAs/(AlGa)Sb heterostructure was grown by molecular beam epitaxy. the superconducting electrodes were formed by thermal evaporation, and the superconducting weak link device was fabricated using a lift‐off process and wet etching.The film thickness of the InAs quantum well layer was 150 Å, and the thickness of the lead alloy superconducting thin film was 2000 Å. the current density and linear current density at 4.2 K for the device length of 0.3 μm were 3 × 104− 105A/cm2and 4.5 − 15 mA/mm, respectively, and theIcRnproduct was estimated to be ∼2 mV. Therefore, the current density andIcRnproduct in superconducting weak link devices using InAs/(AlGa)Sb heterostructure were estimated to be sufficiently large and its potential for superconducting devices has b

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770106

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

年代:1994

数据来源: WILEY

摘要:

AbstractA recess gate depletion‐type InGaAs MISFET has been fabricated by using a thick photo‐CVD SiO2outer layer and on ultrathin MBE Si interface control layer (Si ICL) after HF treatment of air‐exposed InGaAs surface treated by HF. After optimum annealing of the MISFET at 350°C in hydrogen atmosphere for 1 hr, a significant increase of the transconductance was obtained and with a very stable drain current. Maximum effective mobility of 3850 cm2/V.s and a transconductance of 61 mS/mm for a gate length 6 μm were achieved.Based on the observed dependence of gate length on the transconductance, it is found that transconductance as much as 250 mS/mm can be expected for 1 μm gate length even after considering the velocity saturation effect. A drain current drift was controlled below 5 percent after 104s after a gate step voltage was applied.The performance obtained in the present study is comparable to that of photo‐CVD SiO2/Si ICL/InGaAs MISFET fabricated in an in‐line process in ultrahigh vacuum. the result clearly demonstrates that an HF treatment of air‐exposed InGaAs surface is useful for a MISFET

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770107

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

年代:1994

数据来源: WILEY

摘要:

AbstractThe electrical characteristics of the crystallized semiinsulating polycrystalline silicon (SIPOS) film were studied, and its electrical conduction was investigated. It is found that the electrical characteristics of the SIPOS film can be explained by the thermionic emission mechanism. Since the oxygen concentration in the film is higher, the band gap is wider and the resistivity and activation energy are increased. By considering the segregation effect of phosphorus, the surface density of grain boundary traps of the crystallized SIPOS film was derived and the relationship was clarified between the oxygen concentration and the surface density of traps. As the oxygen concentration is increased, the surface density of traps increases. the electrical characteristics of the SIPOS film can be explained better if a Gaussian distribution rather than a single level is assumed for the energy of the grain boundary trap.

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770108

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

年代:1994

数据来源: WILEY

摘要:

AbstractTo a relay with supporting arms in which only the tips with electrical contacts are parallel, AgCdO electrical contacts with Au flash are installed as a normally open contact pair. Within the circuit with dc 30 V ‐ 10 A and a resistive load, it is used as the make‐only, the break‐only, and the make‐and‐break contact pair. the electrical characteristics at each make and break and the contact surface damage after 100 thousand operations were measured.In the sample electrical contact pair with the tips of supporting arms in parallel, it is demonstrated by experiments that arc damages (roughness and black and brown contaminant) occur at the center of the contact surface.The arc trace at the make‐only electrical contact is the narrowest in comparison with two other switching operations and is a milky metallic color surface with many infinitesimal irregularities. In the case of the break‐only and make‐and‐break contacts, large irregularities exist at the center of one of the electrode surfaces. A thick black and brown contaminant exists in this part and surroundings. Also, contact sticking occurred in all samples of make‐only contacts but not in the break‐only contacts.The black and brown contaminant between the contact surfaces prevents locking and increases the contact resistance and the variation width so that they cause a longer duratio

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770109

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

年代:1994

数据来源: WILEY

摘要:

AbstractThis paper proposes the circuit configuration of a current‐mode biquadratic filter which uses a pair of four‐terminal active‐current conveyors (CFCC II) consisting of a current follower attached to a second‐generation current conveyor (CC II). the circuit is composed of one current adder and two current integrators. This configuration is capable of synthesizing arbitrary current‐mode second‐order transfer functions by changing the conditions (grounding or connecting) at the output terminals of the CFCC IIs.Each of the proposed filters has high output impedance so they can be cascaded directly. Moreover, ω0andQ0is determined from the ratio of passive elements, and the element sensitivity is even lower than 0.5. Since all the passive elements are grounded, this configuration is very advantageous to IC fabrication. Again, the effect of imperfection of CFCC II on the transfer function is studied and it is found that ω0is influenced by the current conversion factor of CFCC II andQ0is affected by the imperfection of the integrator. Moreover, it is shown that the operating frequency limits of the filter are determined by the permissible change ofQ0. Each type of filter actually is synthesized, and the useful operation is confirmed b

ISSN:8756-663X    

DOI:10.1002/ecjb.4420770110

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

年代:1994

数据来源: WILEY