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  • Articles  (1,786)
  • Springer  (1,786)
  • American Chemical Society
  • Annual Reviews
  • Blackwell Publishing Ltd
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  • 2005-2009
  • 1990-1994
  • 1980-1984  (1,786)
  • 1982  (859)
  • 1981  (927)
  • Electrical Engineering, Measurement and Control Technology  (1,786)
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  • Articles  (1,786)
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  • 2005-2009
  • 1990-1994
  • 1980-1984  (1,786)
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  • 1
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    Circuits, systems and signal processing 1 (1982), S. 93-104 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A stochastic approximation problem for polynomic operators is formulated. The performance of polynomic operators of various degrees is compared. The effect of causality constraints is also examined.
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  • 2
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    Circuits, systems and signal processing 1 (1982), S. 137-169 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A recently developed algebraic approach to the feedback system design problem is reviewed via the derivation of the theory in the single-variate case. This allows the simple algebraic nature of the theory to be brought to the fore while simultaneously minimizing the complexities of the presentation. Rather than simply giving a single solution to the prescribed design problem we endeavor to give a complete parameterization of the set of compensators which meet specifications. Although this might at first seem to complicate our theory it, in fact, opens the way for a sequential approach to the design problem in which one parameterizes the subset of those compensators which meet the second specification...etc. Specific problems investigated include feedback system stabilization, the tracking and disturbance rejection problem, robust design, transfer function design, pole placement, simultaneous stabilization, and stable stabilization.
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  • 3
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    Circuits, systems and signal processing 1 (1982), S. 267-268 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
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  • 4
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    Circuits, systems and signal processing 1 (1982), S. 433-445 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We describe a recently developed framework for exploring the structure of linear time-invariant models of large systems, and for constructing interpretable or physically-based, reduced-order models that reproduce selected modes of the original systems to a desired accuracy. Application of this framework to constructing lumped approximations for interconnections of lumped and distributed systems is briefly explored.
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    Circuits, systems and signal processing 1 (1982), S. 305-309 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We present speculations on the asymptotic behavior of Hermite-Padé polynomials of type I constructed from a set of functions with common branch points. The proposed form is consistent with all known results and numerical work.
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    Circuits, systems and signal processing 1 (1982), S. 321-343 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Algorithms are derived for representation of double power series by branched continued fractions. Some properties of the branched continued fractions are given. Two new alternative structures for realization of a two-dimensional, zero memory nonlinear transfer characteristic are proposed. These structures permit the design of 2-D systems with relatively low sensitivity of the transfer function to coefficient errors. Generalized equivalence transformations of branched continued fractions are also presented. Illustrative examples are included.
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  • 7
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    Circuits, systems and signal processing 1 (1982), S. 77-92 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Time-invariantn-port networks are considered which are constructed from linear resistors and transformers, and nonlinear inductors and capacitors. A port property is sought which is analogous to the symmetry of the impedance matrix obtained in the linear case. Such a property is found using a stochastic characterization: with all resistors assumed to be at the one temperature and modelled to include the usual thermal noise, a fluctuating noise voltage will be observed at the ports of the networks. With some reasonable restrictions on the nature of the nonlinearities in the reactive elements, the vector of such noise voltages is shown to constitute what is known as a reversible stochastic process; in the linear case, reversibility holds if and only if the impedance matrix is symmetric.
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  • 8
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    Circuits, systems and signal processing 1 (1982), S. 123-134 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Three algorithms for the solution of the eigenvalue problem for a continuously parameterized family of sparse matrices are presented; a continuousLU (orLR) algorithm, a continuousQR algorithm, and a continuous Hessenberg algorithm. Each of the three algorithms may be implemented recursively and the sparsity of the given matrices is preserved throughout the numerical process.
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  • 9
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    Circuits, systems and signal processing 1 (1982), S. 171-202 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract We present two new algorithms to estimate the domain of attraction of the equilibriumx=0 of a nonlinear systemx=f(x). One of these algorithms utilizes quadratic Lyapunov functions while the second algorithm makes use of norm Lyapunov functions. Both of these procedures yield estimates for the domain of attraction which are comparable to those obtained by existing methods; however, the present algorithms appear to be significantly more efficient than existing algorithms. We also show how sometimes the applicability of the above results can be extended to high order systems by invoking the comparison principle. In doing so, we establish some results for the comparison principle which are of interest in their own right. Specifically, we relate the domain of attraction of a low order comparison system to the domain of attraction of a higher order system and we give an interpretation of the comparison principle in terms of stability preserving maps. In order to demonstrate the applicability of the present results, and in order to compare the present results with existing results, several specific examples are presented.
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    Circuits, systems and signal processing 1 (1982), S. 251-266 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This work provides a mathematical framework for topologically-independent analysis of permutation networks. First, a structure-dependent representation is provided using matrices whose entries are switching expressions. Then, a transformation is presented which maps these matrices into structure-independent representations which are matrices whose entries are 0/1 matrices. Algebraic tools for manipulating the second type of matrices are also provided. Notions such as permutations realizable by a network, the rearrangeability property, and series and parallel connections of networks are defined and discussed with regard to the proposed representations.
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  • 11
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    Circuits, systems and signal processing 1 (1982), S. 289-304 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A reliable algorithm, similar to the modifed Kronecker algorithm, is provided for the solution of the Polish polynomial approximation problem. Implicit in this solution is an efficient and reliable method for the algebraic solution of Toeplitz equations.
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  • 12
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    Circuits, systems and signal processing 1 (1982), S. 311-320 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract TheKdV andMkdV multisoliton solutions are found to be generated by rational Stieltjes functions of the non-linearity parameter, each pole of which can be associated with a soliton. The well-known asymptotic emergence of the separate solitons follows at once from the motion of the poles. Successive (n-1/n) Padé approximants to theN-soliton series are considered to show how the solitons are reconstructed from an increasing number of perturbation terms (n ≤N). Their asymptotic behaviour is particularly striking: as time increases the behaviour of then th approximation becomes that of an actualn-soliton solution, constituted by then leading solitons. Furthermore, it turns out that each such Padé approximation satisfies a conservation law: the mass of the approximated solution, equal to that of then solitons included, is conserved.
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  • 13
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    Circuits, systems and signal processing 1 (1982), S. 367-377 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract In this note we review the technique for rational Chebyshev approximation as given by the generalization of the Remes algorithm and point out its connection to the generalized eigenvalue problem for symmetric Hankel matrices. By a classical example and some recent work it can be shown that interpolation with rational functions (even) on equidistant knots may lead to results that are superior to Chebyshev approximation by means of polynomials for comparable numerical work.
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  • 14
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    Circuits, systems and signal processing 1 (1982), S. 407-431 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A problem on optimal approximation of continuous-time linear systems is studied. The performance measure (error) is chosen to be the spectral norm of the difference between the Hankel operators associated with the original system and the approximant. It is shown that the Hankel operators associated with continuous-time systems and the Hankel matrices associated with discrete-time systems are related by an interesting correspondence property via bilinear transforms. This fact is then used to derive the continuous-time results (theory and algorithms) from the established discrete-time ones. Some simple examples are presented.
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  • 15
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    Circuits, systems and signal processing 1 (1982), S. 471-495 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The techniques of scattering and inverse scattering theory are used to investigate the properties of matrix orthogonal polynomials. The discrete matrix analog of the Jost function is introduced and its properties investigated. The matrix distribution function with respect to which the polynomials are orthonormal is constructed. The discrete matrix analog of the Marchenko equation is derived and used to obtain further results on the matrix Jost function and the distribution function.
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    Circuits, systems and signal processing 1 (1982), S. 57-76 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper presents our unified approach to the solution of large system analysis problems. The macromodular behavioral technique combines multiple-logic function macromodeling, functional latency and nested macromodel. We take advantage of the dynamic behavior and the repetitive modular structure of a system to improve the computational efficiency during system analysis. Several Bipolar and MOSFET electronic networks are used to demonstrate the merits of the macromodular behavioral method for large system analysis.
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    Circuits, systems and signal processing 1 (1982), S. 43-56 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract This paper considers the design of an FIR digital filter by interconnecting a number of identical FIR subfilters with the aid of a few additional multipliers and adders. The overall structure is in the form of a tapped cascaded FIR subfilters. A composite method to determine the tapping coefficients along with the coefficients of the subfilter to approximate overall frequency response characteristic is proposed. Several numerical examples illustrating the proposed method are included.
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    Circuits, systems and signal processing 1 (1982), S. 105-122 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Given a passive frequency-dependent source impedance and an active or passive load and a preassigned transducer power-gain characteristic, necessary and sufficient conditions are given for the existence of a lossless reciprocal equalizer which, when operating between the given source and the given load, yields the desired transducer power-gain characteristic. The significance of the present approach is that the realization of the equalizer involves only driving-point synthesis by the Darlington theory.
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    Circuits, systems and signal processing 1 (1982), S. 135-135 
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    Topics: Electrical Engineering, Measurement and Control Technology
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    Circuits, systems and signal processing 1 (1982), S. 203-216 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Using semistate theory forward and reverse binary hysteresis operators are defined from which design equations result for relevant circuits. Through variation of the design parameters swept hysteresis is introduced and experimental results presented on it.
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    Circuits, systems and signal processing 1 (1982), S. 217-231 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract The development of a block-state structure with minimum round-off noise subject to ℓ2-norm dynamic range constraint is outlined. The pertinent equations for scaling and for round-off noise analysis of block-state structures implemented using fixed-point arithmetic are first derived. Next, a lower bound and the global minimum of the output noise due to the round-off of the block-state-variables are derived. A method of deriving the minimum round-off noise block state-structure is outlined. A numerical example is included. With regard to computational complexity and overall noise performance, the block-state realization of recursive digital filters is shown to be superior.
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    Circuits, systems and signal processing 1 (1982), S. 233-249 
    ISSN: 1531-5878
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Although an operational amplifier is a nonlinear device, the existing methods of analysis of circuits with operational amplifiers view it as a linear element which possibly has an infinite gain. As a result, it is not clear to what extent the results thus obtained hold. In this paper we construct a general model of a (nonlinear) circuit containing operational amplifiers. Viewing such a network as an interconnection of a multiport withn operational amplifiers, we give conditions for solvability (i.e., for the existence of an input-output operator), and establish estimates for the error incurred by replacing such a system by an idealized system whose operational amplifiers have infinite gain. In this way we determine ranges for variables within which the traditional linear analysis gives results that fulfill given accuracy requirements.
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    Circuits, systems and signal processing 1 (1982), S. 279-287 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A brief account is given of a number of generalisations of Padé approximants defined and studied over the past twenty years. These generalisations include multi-point approximants, approximants based upon differential equations, multivalued approximants, multivariate approximants, and approximants defined from series of orthogonal functions. The general class of Hermite-Padé approximants is discussed, and various applications are noted.
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    Circuits, systems and signal processing 1 (1982), S. 345-366 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Recent signal processing research suggests that a theory of moments for finite Toeplitz matrices and forms would help in understanding and solving certain model approximation problems. Such a theory is developed in this paper and it is shown how these moment parameterizations can make approximating by low rank Toeplitz matrices tractable. In the case of Toeplitz forms, this moment representation gives a simple solution to the extendibility problem for finite sections of a Toeplitz form.
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    Circuits, systems and signal processing 1 (1982), S. 395-406 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract A theorem is proved which demonstrates that an earlier derived minimum description length estimation criterion is capable of distinguishing between structures in linear models for vector processes. A fairly simple algorithm is described for the estimation of the best model, including its structure and the number of its parameters.
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    Circuits, systems and signal processing 1 (1982), S. 447-470 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Singular value analysis, balancing, and approximation of a class of deformable systems are investigated. The deformable systems considered herein include several important cases of flexible aerospace vehicles and are characterized by countably infinitely many poles and zeros on the imaginary axis. The analysis relies completely on the so-called asymptotic singular value decompositon of the Hankel operator associated with the impulse response of the system. A parametric study of a six-dimensional single-input single-output case is performed.
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    Circuits, systems and signal processing 1 (1982), S. 1-2 
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    Circuits, systems and signal processing 1 (1982), S. 3-41 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Many problems in adaptive filtering can be approached from the point of view of system identification. The close interconnection between these two disciplines is explored in some detail. This approach makes it possible to apply recursive parameter estimation algorithms to adaptive signal processing. Several examples are discussed including: adaptive line enhancement, generalized adaptive noise cancelling, adaptive deconvolution and adaptive TDOA estimation. It is shown how the recursive maximum likelihood algorithm can be used for both FIR and IIR filtering, and some preliminary results are presented. Several alternative algorithms are briefly discussed.
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    Circuits, systems and signal processing 1 (1982), S. 269-278 
    ISSN: 1531-5878
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Conclusions To conclude our discussion we can only confess to our shortcomings as organizers and editors. We have been incomplete, we have been biased, and, worst of all, we have not been able to produce the most essential connections in any firm way. Perhaps our major achievement — if we may say so — has been to point the way to many possible new results and to new research. The field discussed here seemed at first very conventional. May we have convinced the reader that it is not. That the major problems have not been solved. That here lies an open field for system engineers, numerical analysts, and mathematicians.
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    Circuits, systems and signal processing 1 (1982), S. 379-394 
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    Topics: Electrical Engineering, Measurement and Control Technology
    Notes: Abstract Recent results in labelling all contractive intertwining dilations and in studying connections between labellings are presented. These facts are used to describe the general solution of the Carathéodory-Fejér extrapolation problem. This turns out to be useful for some numerical problems such as: computation of the norm of an analytic Toeplitz matrix, an algorithm for detecting reflection coefficients in seismic exploration, and a model for controlling the errors in Wiener prediction.
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    Optical and quantum electronics 13 (1981), S. 35-45 
    ISSN: 1572-817X
    Source: Springer Online Journal Archives 1860-2000
    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The sensitivities of heterodyne and direct-detection systems at CO2 laser wavelengths are compared to illuminate the design principles involved. It is shown that destruction of the temporal coherence of scattered radiation is a significant effect when heterodyne systems are used on targets with internal motion. The complete system and the results obtained are then described. The compact optics head contains a waveguide laser, an acousto-optic modulator and SAW chirp devices; it has 45 mm diameter transmit and receive apertures. Whem many returns are integrated, ranges of several kilometres are obtained off natural targets with an accuracy of 10 m. From the Doppler shift off a moving target, radial velocity can be determined simultaneously with the range when an up-chirp/down-chirp technique is used; an accuracy of better than 1 m s−1 is demonstrated.
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    ISSN: 1572-817X
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    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Description / Table of Contents: Abstract In this paper, the movement of the forward scattering pattern of an unclad fibre illuminated by a laser beam perpendicular to its axis is studied when the fibre is rotated. The existence of a linear relation between the coefficients of the Fourier series which represent the angular shift of a bright fringe and the fibre cross-section is shown. Thus it is possible to know to an excellent approximation the shape of the cross-section by monitoring the fringe movement.
    Notes: Résumé Dans cet article, on étudie le diagramme de diffusion vers l'avant d'une fibre optique d'indice uniforme éclairée par un faisceau laser perpendiculaire à son axe lorsqu'elle tourne sur elle-même. On montre qu'il existe une relation linéaire entre les coefficients des développements en série de Fourier des fonctions représentant le déplacement angulaire d'une frange brillante et le contour de la section. Le mesure du déplacement d'une seule frange permet de connaître avec une excellente approximation la forme de la section.
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    Optical and quantum electronics 13 (1981), S. 91-94 
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    Optical and quantum electronics 13 (1981), S. 141-146 
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    Notes: Abstract A simple method for adjusting light coupling between two waveguides is presented. The method involves trimming the interaction length by loading a metal film on to one of the coupled-waveguides. It is effective only for the TM mode, and trimming can be achieved very simply. The operational principle is experimentally examined using an optical directional coupler fabricated inc-plate LiNbO3.
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    Optical and quantum electronics 13 (1981), S. 153-163 
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    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The problem is considered of designing an optimum receiver for a digital fibre optic communication system with Poisson signal statistics and additive Gaussian noise when received pulses are overlapped by the transmission channel dispersion. The power signal to noise ratio is the optimization criterion. Like the minimum mean square error optimality criterion, this optimization yields a cascade of prefilter and transversal filter with certain tap gains. The tap gains are different according to whether the minimum of mean square error or the maximum of signal to noise ratio is sought. Numerical comparison between average error rates shows that the maximum signal to noise ratio optimum filter is the better one, and leads to a receiver design with lower average error rate.
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    Optical and quantum electronics 13 (1981), S. 181-186 
    ISSN: 1572-817X
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    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract The direction of light propagation in integrated optical circuits can be inverted at the substrate edges by halved directional couplers with mirror planes at the substrate end facets. Thus the output and input of a directional coupler can be fed back on to the substrate forming a periodic spectral filter with extremely high frequency sensitivity. The filter characteristic is analysed with respect to frequency, feedback efficiency, parameters of the directional coupler and temperature. The filter pass and stop bands can be controlled electrically.
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    Optical and quantum electronics 13 (1981), S. 229-239 
    ISSN: 1572-817X
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    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract A new approach to the steady-state solution of the optical power flow equation in multimode fibres is presented. It takes into account the dependence on the modulation frequency of the optical guided power, starting from a very general trial solution. The steady-state attenuation coefficient and optical power distribution (in amplitude and delay) can be numerically evaluated for any kind of index profile and fibre perturbation.
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    Optical and quantum electronics 13 (1981), S. 415-419 
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    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Notes: Abstract Coupled partial differential equations are derived, consistent with localized use of one-dimensional theory in a thin volume hologram, from modifications to both one-dimensional and two-dimensional theory. The approximations inherent in the model and the range of validity of the solution are discussed.
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    Optical and quantum electronics 13 (1981), S. 393-400 
    ISSN: 1572-817X
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    Topics: Electrical Engineering, Measurement and Control Technology , Physics
    Description / Table of Contents: Abstract In single-mode fibres, the propagation of laser pulses with temporal energy profile P(t) induces a self-phase modulation (due to the optical Kerr effect) which increases along the fibre. Under particular conditions this phase shift is proportional to the derivative of the temporal energy pulse profile at the fibre input. In this paper we describe experiments on self-frequency modulation with laser pulses which exhibit various controlled temporal energy profiles. The experimental results agree quite well with analytic calculations previously given by Stolen and Chinlon Lin; here, they are explained within the framework of a new geometrical interpretation of various properties of pulse spectra which exhibit smooth amplitude modulation and large phase modulation.
    Notes: Résumé La propagation d'une impulsion laser de profil énergétique temporel P(t) dans une fibre optique monomodale s'accompagne, par effet Kerr optique, d'une modulation de phase qui s'accumule tout au long de la fibre. Sous certaines conditions particulières, ce déphasage est proportionnel áP(t): la loi de modulation de fréquences que présente l'impulsion à l'extrémité de la fibre est alors proportionnelle à la dérivée par rapport au temps du profil énergétique temporel de l'impulsion injectée à l'entrée de la fibre. Dans cet article, nous décrivons des expériences d'automodulation de fréquences d'impulsions présentant des profils temporels énergétiques variés et contrôlés. Les résultats expérimentaux obtenus sont en bon accord avec les prévisions analytiques formulés par Stolen et Chinlon Lin; ici, nous les expliquons dans le cadre d'une interprétation inédite de quelques propriétés des spectres d'impulsions peu modulées en amplitude, largement modulées en phase.
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    Optical and quantum electronics 13 (1981), S. 493-507 
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    Notes: Abstract A stable resonator incorporating a suitably adjusted telescope gives reliable operation of an Nd:YAG laser with a large-volume TEM00 mode. The telescope adjustment is chosen to minimize the effect of focal length variations in the laser rod and at the same time ensures the optimum mode-selection properties of a confocal resonator. Simple approximations applied to the ray transfer matrices allow a detailed analysis of the resonator to be performed. This analysis yields simple design equations relating the mode spot sizes, resonator length, telescope magnification and defocusing, and diffraction losses. Experimental results show excellent agreement with the results of this analysis.
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    Optical and quantum electronics 13 (1981), S. 525-525 
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    Optical and quantum electronics 14 (1982), S. 217-223 
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    Notes: Abstract General results are given for the influence of coherence and misalignment on the complex amplitude addition and subtraction by holographic Fourier transformation. For the method of Gaboret al. we have investigated the effects of longitudinal and transverse misalignment of the recording material between the first and second exposure. A method for complex addition and subtraction of Fourier transforms is investigated also.
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    Optical and quantum electronics 14 (1982), S. 245-251 
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    Notes: Abstract The excite-and-probe technique was used to study the optically induced charge carrier concentration dependence of the reflectivity of semiconductors, both experimentally and theoretically, in the case of an exponential carrier distribution. The second harmonic of an Nd : YAG laser (pulse duration 25 ps) was used as the exciting beam; the fundamental wave served as the probe beam. At a carrier concentration of about 2.5×1021 cm−3 a minimum reflectivity was obtained if the angle of incidence was greater than 40°. For increasing absorption constants of the semiconductor at the exciting frequency, this minimum value of the reflectivity was shown to increase. The dependence of the reflectivity on the exponentially distributed carrier concentration was studied experimentally for thin amorphous silicon films produced by the glow-discharge technique. For an absorption constant of 6×105 cm−1 at 532 nm, good agreement was found between the numerical calculations and the experimental results.
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    Optical and quantum electronics 14 (1982), S. 253-261 
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    Description / Table of Contents: Abstract This paper deals with self-focusing of picosecond laser pulses due to the optical Kerr effect in CS2. It describes experimental techniques by which the self-focusing process can be controlled with a good degree of spatial and temporal reproducibility. It includes applications to the frequency modulation of light pulses. Appropriate combination of this modulation with linear amplitude filtering results in pulse shortening of a 30 ps pulse by a factor of 30.
    Notes: Résumé Nous décrivons plusieurs techniques expérimentales qui permettent de maîtriser le phénomène d'autofocalisation d'un faisceau laser ‘picoseconde’ dans un matériau présentant l'effet Kerr optique. Sous certaines conditions, ce phénomène est suffisamment prévisible et reproductible dans le temps et dans l'espace pour produire des impulsions picoseconde présentant certaines lois contrôlées de modulation de fréquences temporelles. Enfin, nous montrons comment des impulsions laser de durée initiale 30 ps modulées convenablement en fréquence par autofocalisation contrôlée dans CS2 peuvent être raccourcies d'un facteur 30 environ par filtrage passif d'amplitude.
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    Optical and quantum electronics 14 (1982), S. 280-282 
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    Optical and quantum electronics 14 (1982), S. 321-326 
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    Notes: Abstract Hysteresis is demonstrated in the light output versus current characteristics of twin-stripe injection lasers subject to optical injection. The sensitivity of the device to optical injection is adjustable and allows an adjustable switch for bistable operation to be defined.
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    Optical and quantum electronics 14 (1982), S. 331-338 
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    Notes: Abstract The radiation emitted spontaneously by a semiconductor which has been excited for a very short time decays exponentially with a time constant that depends on the recombination rate of electrons and holes. This recombination rate is the combination of radiative and nonradiative transition rates between conduction and valence bands of the semiconductor. The radiative recombination rate depends on the density of states of the electromagnetic field, which can be made to be dependent on the geometry. In this paper, we report on the dependence of the fluorescence lifetime upon the thickness of active thin films. For systems in which the radiative recombination rate is dominant over the nonradiative ones, the total recombination time can be changed by suitable modifications of the thickness of the film. In this situation, the nonradiative rate can be evaluated. We present experimental results for the case of cadmium sulphide (CdS) thin films.
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    Optical and quantum electronics 14 (1982), S. 339-346 
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    Notes: Abstract A new technique of alternate two-wavelength oscillation of a CO2 laser is discussed for application to various differential absorption spectroscopic measurements. Power-balanced, two-adjacent branch oscillation using a single CO2 laser was achieved by modulating the angle of a mirror inside the laser cavity and adjusting automatically the cavity length. The two-wavelength modulation frequency was extended up to about 1.2 kHz. Line tuning and power modulation characteristics were studied. The laser was used in long-path differential absorption measurements of ethylene air pollution molecules to demonstrate the capability of this power-balanced, two-wavelength oscillation method. The minimum detectable absorption was nearly 1×10−3 in a short-path cell experiment and 3×10−3 in a long-path experiment.
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    Optical and quantum electronics 14 (1982), S. 371-374 
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    Optical and quantum electronics 14 (1982), S. 425-431 
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    Notes: Abstract The distinction between coherent and incoherent nonlinear optical interactions is established at the beginning of the paper. In the first part parametric up conversion (PUC) by coherent nonlinear optical mixing of the strong pumping radiation with weak input radiation is treated with respect to statistical properties of generating radiations. The efficiency of PUC is calculated by means of the conserved statistics method. It is shown that the efficiency of PUC depends upon the photon statistics of the strong pumping radiation only, namely, it decreases with increasing fluctuation level in the pumping radiation. The fourth-order statistics of generated sum-frequency radiation is calculated in the first approximation of the iterative solution. The statistics of both generating radiations are projected into the statistical distribution of the resulting sum-frequency radiation in the same way at the beginning of the process.
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    Optical and quantum electronics 14 (1982), S. 445-451 
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    Notes: Abstract This paper presents a theoretical and experimental study of the application of the near field technique to the measure of radiance of light emitting diodes and laser diodes. We have shown the possibilities and the limitations of this technique.
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    Optical and quantum electronics 14 (1982), S. 465-466 
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    Optical and quantum electronics 14 (1982), S. 483-499 
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    Notes: Abstract Snyder's equivalent step-index method is extended to the case of graded profiles with a depressed cladding. This method is then used to determine the limit of monomode operation. Comparison with the results obtained by an exact numerical technique is made for a large variety of simulated profiles, including those with ripples in the cladding. Conclusions are drawn concerning the sensitivity of various profile-shapes to such ripple structure. The method is applied also to measured profiles, reconstructed by a well-known tomographic procedure. In this latter case a comparison is made with experimentally determined values.
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    Optical and quantum electronics 14 (1982), S. 525-537 
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    Notes: Abstract A new theoretical treatment of the dispersion theory for rectangular optical waveguides is presented. The theoretical basis of the effective dielectric constant method is investigated, and it shows how corrections can be calculated systematically. The result is a new set of eigenvalue equations, simple in form, and which provide very accurate values for the propagation constant.
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    Optical and quantum electronics 14 (1982), S. 547-556 
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    Notes: Abstract A theoretical study is presented of the stationary energy transfer between two beams in the writing of a reflection hologram in a dynamic medium. The intensities of the two beams both inside the medium and at the surfaces are determined as a function of absorption coefficient, the effective coupling constant, the initial intensity ratio and the thickness of the medium. Numerical results obtained from the computer calculations are presented in graphical form.
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    Optical and quantum electronics 13 (1981), S. 19-34 
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    Notes: Abstract A theoretical investigation of the resonantly enhanced, Raman-induced Kerr effect (resonance-RIKE) is given, taking into account the resonance absorption of the laser wave and the population of excited electronic states. Line shape, maximum amplification and optimum conditions for the resonance-RIKE from the ground state as well as for the resonance-RIKE from an initial excited electronic state are discussed in detail. The possibility is studied of applying this method to the investigation of the vibrational structure of excited electronic states in molecules.
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    Optical and quantum electronics 13 (1981), S. 187-192 
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    Notes: Abstract A two-wavelength oscillation C02 laser was constructed for the differential absorption measurement of low concentrations of atmospheric trace molecules and pollution molecules. A diffraction grating was alternately angle-modulated for the two-branch oscillation using a single C02 laser. The output power of the two wavelengths was balanced to be equal. With these characteristics, the phase-sensitive detection technique can be applied to give highly sensitive detection of the received power difference, which is proportional to the absorption in the optical path of the transmitted beams. A differential absorption spectrometer was used to demonstrate the usefulness of this two-wavelength laser oscillation method incorporating the output power balancing technique. The concentration of ethylene molecules was detected in a calibration cell and was also measured in real time in the exhaust of a combustion engine. From these results it has been shown that this differential absorption scheme offers a minimum detectable absorption of approximately 0.8%.
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    Optical and quantum electronics 13 (1981), S. 201-208 
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    Notes: Abstract The application of detector arrays for the estimation of optical beam position is considered. An estimation algorithm is synthesised, and estimator performance is analysed. Estimator performance depends on the number of detectors in the array and on the received radiation and its associated shot noise. It is shown that by choosing an appropriate number of detectors in the array, the designer can always drive the estimator into shot-noise-limited operation. In this case, the performance may be either quantum-limited or background-noise limited, depending on the energy of the optical beam and on the background field.
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    Optical and quantum electronics 13 (1981), S. 217-224 
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    Notes: Abstract A numerical technique, based on transforming the scalar wave equation to a finite interval before discretization is applied, is proposed for the solution of the scalar wave equation defining the modal fields and propagation constants of optical fibres. It is used to compute the propagation constants and modal fields of weakly guiding fibres of circular cross-section when the refractive index profile has a Gaussian or smoothed-out form. The smoothed-out profiles are studied because they vary continuously from the Gaussian to the step profile. Results are compared with and shown to be accurately approximated by simply explicit functions, dependent only on the fibre parameter.
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    Optical and quantum electronics 13 (1981), S. 71-83 
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    Notes: Abstract A new approach to modal propagation for optical fibres with arbitrary refractive index profile, based on the Bubnov-Galerkin method, is developed. The theory furnishes an accurate description of modal propagation constants and field distributions. When tested for step-index and truncated parabolic profiles the method is found to agree with the known exact results.
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    Optical and quantum electronics 13 (1981), S. 95-107 
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    Notes: Abstract This paper presents a theoretical study of the nonlinear propagation ofN polarized intense waves in a macroscopically isotropic medium. General formulae are obtained for the polarization states and the nonlinear dependence of the index of refraction. In the absence of self-focusing, it is shown thatN linearly or circularly polarized waves retain their initial state of polarization during propagation. Results have been tabulated for the refractive indices and the polarization states ofN waves according to their initial polarization states. In the self-focusing regime, only circularly polarized waves conserve their polarization. This paper presents a description of the phenomenon of cross-focusing: in a certain power range, a wave of higher power induces self-focusing of a wave of lower power, whereas in some other situation, a stronger wave self-defocuses in the presence of a weak wave. In one of the situations, the phenomenon of an oscillatory waveguide is also exhibited. The polarization states of two waves in the self-focusing range have also been discussed.
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    Optical and quantum electronics 13 (1981), S. 147-152 
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    Notes: Abstract Theoretical expressions for the high-frequency behaviour of a p-n photodiode, limited by theRC-time constant and the diffusion time to the junction, are given. Comparisons with temporal and frequency response measurements on an HgCdTe photodiode have been performed. The good agreement between theoretical and experimental data suggests that this type of high-mobility semiconductor photodiode can be described using the derived model, in which a constant, saturated diffusion velocity is assumed.
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    Optical and quantum electronics 13 (1981), S. 193-199 
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    Notes: Abstract The need to obtain a coherent output beam may impose severe constraints on the design of lasers with annular amplifying regions. One solution to the mode control problem involves resonant cavities in which the optical fields make more than one pass through the amplifying medium before returning to their starting point on the cavity mirror. Such multipass cavities and the resulting phase-compensated beam modes are considered in detail.
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    Optical and quantum electronics 13 (1981), S. 209-215 
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    Notes: Abstract An investigation was made of the spectra, the kinetics of induction and thermal decay and the dichroism of the photoinduced triplet absorption band in a rigid solution of fluorescein in orthoboric acid. Dynamic holographic recording was possible on this material. An experimental study was conducted into the polarizing properties of the volume transmission holograms. The experiments on four-wave mixing with continous laser light revealed a very high resolution for this rigid solution when used as a medium for optical recording. As a result of the investigations, some possible applications of the rigid solution of fluorescein are pointed out.
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    Optical and quantum electronics 13 (1981), S. 247-250 
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    Optical and quantum electronics 13 (1981), S. 259-293 
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    Notes: Abstract The review covers both the principles of laser rangefinders and some of their many applications. Descriptions are given of the various types of laser sources used in rangefinders, followed by sections on atmospheric propagation, target effects and receivers. Some of the applications covered are: rangefinders for military use based upon ruby, neodymium and holmium; lunar and satellite ranging systems; instruments for measuring cloud-base heights and sea-depths; surveying instruments based upon semiconductor lasers; applications of CO2 lasers using direct or heterodyne detection; aerosol pollution lidars, etc.
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    Optical and quantum electronics 13 (1981), S. 348-351 
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    Optical and quantum electronics 13 (1981), S. 433-435 
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    Optical and quantum electronics 14 (1982), S. 89-91 
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    Optical and quantum electronics 14 (1982), S. 157-167 
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    Notes: Abstract A new optical-optical modulator for the infrared region (4μm 〈λ 〈 11μm) is described. It is based on the tuning of the transmission of a plane parallel tellurium slab by free carriers created by multiphoton absorption of 10.6μm and 5.3μm radiation at room temperature. The operation of this device is described by a simple theory using the plane-wave approximation and the Drude-Zehner model. The assumptions of this theory were fulfilled by the experimental conditions, permitting a quantitative analysis of the registered modulations. Under certain working conditions pulse shortening (170 ns pulses ofλ=5.3μm were shortened by up to 20 ns) and fast switch-on of the device (switch-on time ⩽2 ns) were observed. Moreover, the modulator exhibits limiter action and optical bistability which, for the first time, is observed in an intrinsic semiconductor device at room temperature.
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    Optical and quantum electronics 14 (1982), S. 61-66 
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    Notes: Abstract The design and performance of a high-speed optical receiver for the 1.3μm and 1.5μm wavelength regions is described. The receiver comprises an InGaAs PIN photodiode feeding into a bipolar transimpedance preamplifier. Measured receiver characteristics are found to compare favourably with theoretical predictions.
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    Optical and quantum electronics 14 (1982), S. 73-76 
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    Optical and quantum electronics 14 (1982), S. 85-88 
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    Optical and quantum electronics 14 (1982), S. 95-143 
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    Notes: Abstract This review discusses the requirements and constraints on components for long-wavelength monomode systems. In particular it critically reviews the current status of fibre, splicing, cabling, laser, detector, receiver and systems research; emphasis is placed on practical achievements rather than just speculative possibilities. The review concludes with a brief assessment of the future role of guided-wave optical devices.
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    Optical and quantum electronics 14 (1982), S. 225-236 
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    Notes: Abstract We apply an operator method, based on the scalar wave equation, to study the propagation of a Gaussian light beam in an optical fibre with an arbitrary, elliptically symmetric refractive-index profile. We discover that ray optical results, while not capable of predicting the rapid distortion of an optical beam in a non-ideal refractive-index profile, successfully simulate the general form of the optical power distributions, even in non-ideal profiles. We find that the propagation patterns for elliptical fibres with and without a strongly scattering central index dip show several unexpected similarities.
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    Optical and quantum electronics 14 (1982), S. 201-215 
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    Notes: Abstract A general method is introduced for modelling coherent radiative and propagational processes at optical and near-optical frequencies in degenerate transitions of gaseous atomic and molecular systems. A ‘Blochtensorial’ expansion is used to describe the coherent behaviour of the system, and is applicable to P-, Q- and R-type transitions. Time-dependent solutions of the high-order multipole Maxwell-Bloch equations are obtained for irradiation of the systems by both linearly polarized and circularly polarized incident fields. These lead to important predictions of pulse evolution behaviour in degenerate amplifier and absorber systems.
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    Optical and quantum electronics 14 (1982), S. 237-243 
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    Notes: Abstract Single-mode operation of an atmospheric-pressure TE CO2 laser is reported. Single longitudinal mode emission has been achieved by incorporating a low-pressure, transversely excited gain section in the same laser cavity as the atmospheric-pressure section. The effects of different resonator configurations on the system modal behaviour have been investigated and it is shown that unstable resonators are particularly suitable for controlling the transverse mode structure with a complete coverage of the excited medium. With an unstable resonator configuration, formed by a metallic convex mirror and a plane diffraction grating, single longitudinal and single transverse mode output pulses with energy up to 2 J have been produced on more than 40 lines of both the 9.4μ m and 10.4μ m bands. This technique can easily be scaled to larger aperture devices at higher extracted energies.
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    Optical and quantum electronics 14 (1982), S. 375-389 
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    Notes: Abstract The influence of an external dispersive resonator on the emission properties of a double heterostructure semiconductor laser operating at room temperature has been investigated. The proper design of the external resonator (frequency selectivity and efficient back-coupling of the radiation leaving the diode) demonstrates that a laser with optical feedback can show bistability and hysteresis phenomena. The dispersive bistability has its origin in the dependence of the refractive index on carrier density, temperature and optical power. Hysteresis curves have been measured by changing the injection current or by tuning the dispersive element. We have found a threshold in the injection current for the onset of the hysteretic behaviour. Moreover, a theoretical model has been established to explain the essential features of the experimental results. Hysteresis cycles for different experiments have been calculated.
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    Optical and quantum electronics 14 (1982), S. 413-417 
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    Notes: Abstract The design of tunable large angular aperture TeO2 noncollinear acousto-optic filters for use in the 1.0–1.6μm region is discussed. It is shown that it is possible to maximize the angular aperture of such a filter by the correct choice of the direction for the acoustic wave vector and that this required direction is independent of the operating wavelength in the range 1.0–1.6μm. The theoretical model adopted is verified by comparison with experimentally measured filter characteristics and the design of filters with narrow bandwidths and low power requirements is discussed.
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    Optical and quantum electronics 14 (1982), S. 433-444 
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    Notes: Abstract Parametric up conversion (PUC) by incoherent nonlinear optical mixing of second-order coherent strong pumping radiation and another weak chaotic input radiation with a finite spectral width is treated in the second part of this paper. The efficiency of PUC is calculated in the second approximation of the iterative method. It is shown that in the case of perfect phase matching the efficiency of PUC decreases with increase of both the spectral width of the input radiation and the dispersion of medium, whilst at considerable values of phase mismatch the reverse effect appears. The spectral distribution of the resulting sum-frequency radiation is calculated in the first approximation of the iterative method. There is a general tendency to narrowing of the spectral distribution of the generated radiation in the course of PUC. Moreover, when there is a phase mismatch present, a spectral shift of the central maximum of generated radiation towards the blue or red region, according to the signs of the phase mismatch and the typical dispersion coefficient, appears in the later phases of the PUC.
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    Optical and quantum electronics 14 (1982), S. 467-474 
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    Notes: Abstract The propagation of off-axis Gaussian beams through an optical system is described in the paraxial approximation. The formulae for the second harmonic power for stationary focused noncollinear SHG is given. Numerical results and analytical approximations for limiting cases are provided. The theory is applied to the problem of background of noncollinear SHG in pulse duration measurement techniques.
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    Optical and quantum electronics 14 (1982), S. 501-513 
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    Notes: Abstract Onset of the dissociative-attachment instability requires that the rate coefficient for electron detachment (k d) from negative ions be below a critical value. The predominant negative and positive ions in a CO2∶N2∶He gas-discharge plasma are known to change with time. As secondary by-products form and the predominant negative-ion species changes from CO 3 − to NO 2 − , a decrease ink d occurs destabilizing the discharge. Since NO 2 − and NO 3 − are largely unreactive with respect to associative detachment,k d depends in a sensitive fashion on the concentration of certain minority negative ions (O−, O 2 − ) and neutrals (CO, O, N). The sufficient conditions for the dissociative-attachment instability are much less sensitive to changes in the electron-ion and ion-ion recombination rate coefficients resulting from the ion aging process.
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    Optical and quantum electronics 14 (1982), S. 539-546 
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    Notes: Abstract Based on the theory of coupled waves the simultaneous diffraction of two waves at a plane dielectric reflection volume hologram is described. By analogy to the transmission volume grating the intensities of the output beams strongly depend on the phase shift between the incident waves and the phase shift of the grating with respect to the interference structure of the read-out waves. This gives the possibility of transferring the incident energy from one wave into the other and can be used for the modulation or deflection of the reconstructed beams. The separate determination of the different kinds of phase shifts by intensity or phase measurements is discussed.
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    Optical and quantum electronics 13 (1981), S. 335-343 
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    Notes: Abstract The propagation characteristics of inhomogeneous optical fibres with different types of deformed core boundaries are analysed by a perturbative approach based on the scalar wave equation. The influence of the core deformation on the propagation constants and group delays is studied in detail for the truncated parabolic profile. We can conclude from this analysis that the difference in group delays due to deviation from circularity does not cause any difficult tolerance problems for realistic deformations and is generally negligible for practical optical fibres.
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    Optical and quantum electronics 14 (1982), S. 81-84 
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    Optical and quantum electronics 14 (1982), S. 92-93 
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    Optical and quantum electronics 14 (1982), S. 145-155 
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    Notes: Abstract The influence of spatial saturation modulation of both the amplifier and absorber in a laser with a Fabry-Perot resonator, and of the associated Bragg-reflection, on the frequency-dependent losses necessary for single-frequency operation, as well as on the frequency synchronization of three modes, has been examined. Conditions for mode selection and mode synchronization are given. To achieve single-frequency operation in a laser with a Fabry-Perot resonator the loss difference between the mode to be selected and modes to be quenched has to be proportional to the Bragg losses of the selected mode suffered by its self-induced grating. The proportionality factor depends on the length and position of the amplifier in the cavity. In the case of a short amplifier and a short absorber inside the resonator, the discussion of conditions for synchronization of three modes shows that the synchronization regime is also determined by the position of the absorber.
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    Optical and quantum electronics 14 (1982), S. 183-187 
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    Notes: Abstract A simple method for measuring dispersion in long-span single-mode fibre, by using directly modulated multi-longitudinal mode semiconductor lasers, is proposed. Experimental values for single-mode fibre dispersion over a 44.3km span at 1.1 and 1.5μm are 19 and 17 ps km−1 nm−1, respectively, and are in good agreement with Gloge's theory. The zero-dispersion wavelength estimated from the experimental results is about 1.28μm, 8 nm shorter than the theoretical value.
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    Optical and quantum electronics 13 (1981), S. 469-486 
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    Notes: Abstract A rigorous treatment of the optimal receiver for digital fibre optic systems is presented. Starting from physical and theoretical considerations, a signal-plus-noise model is obtained for the input stage of an optical receiver. The model is used to set up a hypothesis-testing problem for a transmitted sequence of binary independent and identically distributed information symbols. The Bayes optimal receiver is next derived using the Karhunen-Loève expansion, and upper bounds of the Chernoff type are obtained for its performance. The derived formulae are applied to a typical system and numerical results are obtained which show an improvement of at least 4 db in favour of the optimal receiver when compared to its conventional counterpart at a 10−9 error rate.
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    Optical and quantum electronics 13 (1981), S. 352-352 
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    Optical and quantum electronics 13 (1981), S. 379-383 
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    Notes: Abstract The nonlinear coefficientχ (3) (3ω) of the singly ionized atoms Mg II and Ca II has been calculated for a wide range of incident wavelengths from v.u.v. to i.r. In some parts of the spectrum the magnitude of the nonlinear susceptibility is comparable to that of the alkali metal vapours.
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    Optical and quantum electronics 13 (1981), S. 401-410 
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    Description / Table of Contents: Abstract Using coherent optical spectroscopic techniques, we perform a temporal selection of the different modes propagating in a multimode optical fibre, with subpicosecond resolution. The intensity patterns of the excited modes are visualized by optical filtering of a Fourier hologram. An experimental demonstration is presented in the elementary case of a bimodal fibre.
    Notes: Résumé En utilisant des techniques de spectroscopie optique cohérente, on réalise, avec une résolution subpicoseconde, une sélection temporelle des différentes modes qui se propagent dans une fibre optique multimodale. La structure spatiale, en intensité, des modes excités est visualisée par filtrage optique d'un hologramme de Fourier. Une démonstration expérimentale est présentée dans le cas élémentaire d'une fibre bimodale.
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    Optical and quantum electronics 14 (1982), S. 25-40 
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    Notes: Abstract A six-temperature Boltzmann-equilibrium kinetics model has been developed for simulating the performance of fast-axial-flow, longitudinal-discharge CO2 lasers. The model includes the effects of electrical excitation, VV and VT collisional relaxation, thermal energy transport, distributed optical losses, and coherent radiation extraction for a CO2/N2/He/H2O mixture. Numerical predictions from the model are compared with experimental results obtained with a 2.5 kW device.
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    Optical and quantum electronics 14 (1982), S. 177-181 
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    Notes: Abstract The use of light injection to modify the lateral gain profile in twin-stripe injection lasers is described and consequent movement of the lasing optical field is demonstrated. A method of quantifying the sensitivity of the device to light injection is described and used to examine the dependence of optical instability upon injection current.
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    Optical and quantum electronics 14 (1982), S. 189-200 
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    Notes: Abstract The equations describing the interaction between an optical beam and an acoustic wave are derived using plane waves derived from elementary scattering sources. The results obtained are in good agreement with other well-known methods such as the differential difference equation approach. The equations are applied to the acousto-optic interaction in the weak and strong approximations and also to the scattering of finite-width optical beams with rectangular and Gaussian profiles. It is shown that in both cases the second or backscattered beam (A′ 0) produces a substantial modification in the through beam (A 0) resulting in an intensity null at some point in the beam profile. Equations are derived for the diffraction efficiency in finite-width beams and it is shown that in order to achieve maximum efficiencies it is essential to use small values of the parameter γ =Lθ B/W.
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    Optical and quantum electronics 14 (1982), S. 169-176 
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    Notes: Abstract The properties of the twin-stripe injection laser are examined as functions of two parameters governing diffusion and waveguiding effects in the device. The carrier diffusion rate, as determined by the ambipolar diffusion coefficient,D, is shown to influence the current range over which lasing action is maintained. The curvature of the nonlinear portion of the light-current characteristic of the device is also changed asD is altered. It is found that the relative strengths of the guiding mechanisms acting upon the optical field further influence the characteristics of the structure.
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    Optical and quantum electronics 14 (1982), S. 277-279 
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    Optical and quantum electronics 14 (1982), S. 311-315 
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    Notes: Abstract Dichromated gelatin would be the most suitable irreversible medium for holographic recording but for its low sensitivity. The efficiency of the photoinduced reduction of the chromium ion increases considerably if superfine grains of silver halide crystals are present in the layer. The light sensitivity achieved is about 10 times better than that of dichromated gelatin layers, obtained and processed in the conventional way.
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    Optical and quantum electronics 14 (1982), S. 327-330 
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    Notes: Abstract The influence of interference due to weak reflections from anti-reflection coated surfaces in CO2 laser optics is discussed and analysed. In certain cases quite low reflection levels (∼1%) are shown to lead to uncertainties in the mirror transmission coefficient or produce a non-uniform power loading on the mirror surface, resulting in damage.
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