2025Article de revue
Noise-driven multi-scroll hidden attractor destruction in optical injection semiconductor laser system
A. D. Mengue, D. E. Essebe, B. Z. Essimbi
Optical and Quantum Electronics
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Enseignant-chercheur à l’Université de Yaoundé I. Grade : Professeur.
Publications scientifiques
A. D. Mengue, D. E. Essebe, B. Z. Essimbi
Optical and Quantum Electronics
A. D. Mengue, D. E. Essebe, B. Z. Essimbi
Optical and Quantum Electronics
A. D. Mengue, E. J. R. Olinga, B. Z. Essimbi
Chaos An Interdisciplinary Journal of Nonlinear Science
In this paper, we investigate bifurcations of equilibria and transients by using modified rate equations of semiconductor lasers (SCLs) subjected to optical injection. An analytical study is performed to demonstrate some two-parameter bifurcations, inter alia, Bogdanov-Takens and Gavrilov-Guckenheimer bifurcations. A detailed numerical study based on the multiparametric bifurcation method and using 3D-plots and projections reveal a rich locking dynamics of SCLs. In this way, a so-called zero frequency detuning well is highlighted in the vicinity of a Hopf bifurcation confining minimal states of the larger Lyapunov exponent in injection locking curves. Three-parameter bifurcation curves mainly underscore cusp bifurcation and resizing of its multi-equilibrium region by the specific control parameter defined in this model. The bursting phenomenon observed in the transient regime is discussed by using various numerical approaches wherefrom another quantifying method tapping into two-parameter bifurcation analysis is proposed. Thereafter, metastable chaos dynamics supported by spiraling relaxation oscillations is also investigated as well as planar saddle-node bifurcations with three homoclinic orbits for high positive and negative detunings. At last, zero α-factor effects contribute to drastically shrink the unlocking region of SCLs, twofold increase in Hopf bifurcation along with evidencing of complex chaotic sine-shaped and folded torus-shaped attractors.
M. Meli Dzoyem, A. D. Mengue, B. Z. Essimbi
The European Physical Journal Plus
A. D. Mengue, D. E. Essebe, B. Z. Essimbi
Research Square
Abstract In this paper, we consider the modified model of semiconductor lasers (SCLs) subjected to optical feedback and we showcase the main dynamical features that emerge in this system by emphasizing the prominent role played by the new control parameter namely the mean of effective gain coefficient (MEGC). A detailed linear stability analysis is performed wherein many approaches allow to put forth accurate limits of steady state, relaxation oscillation and chaotic areas controlled by MEGC. The process of the modulational instability is stuck out and the diagonal break-up of the ellipsoid enclosing external modes and antimodes is carried out leading to coherence collapse phenomenon and the excited mode scattering that is gradually extended by increased MEGC states. The route to the narrow linewidth at the limit conditions is fulfilled under the drastic impact of MEGC likewise the dependency of Hopf bifurcation parameters, as well as mode excitation and induced destructive interference of optical feedback in the modified potential well model.
Duplex S. Mbieda Petmegni, Frank G. Mbieda Ngomegni, Alain M. Dikandé, B. Z. Essimbi
Optics Express
D. E. Essebe, A. D. Mengue, B. Z. Essimbi
Optical and Quantum Electronics
Folla Kamdem Jérôme, M.L. Crespo, Evariste T. Wembe, Mohammad Arif Sobhan Bhuiyan, A. Cicuttin, B. Z. Essimbi et 1 autre(s)
IET Circuits Devices & Systems
Abstract The preamplifier module is a crucial element while designing dynamic latch comparators. The traditional double tail comparator utilizes a differential pair as the preamplifier stage. The circuit is generally suffered from high power dissipation and low comparison speed. This research reports the design and implementation of a low‐offset, low‐power and high‐speed dynamic latch comparator. In this work, an enhanced differential pair amplifier is employed in the preamplifier stage, to improve the power dissipation and the comparison speed of the device. A custom latch structure with rigorous transistor sizing was implemented to avoid short circuit current and mismatch in the module. The effective trans‐conductance of the cross‐coupled transistors of the latch was therefore improved for an optimal time delay solution. The equation associated with the delay was derived and the parameters that embody the speed were identified. The design has been validated by corner analysis and post‐layout simulation results in 65 nm CMOS technology process, which reveals that the proposed circuit can operate at a higher clock frequency of 20 GHz with a low‐offset of 4.45 mV and 14.28 ps propagation delay, while dissipating only 67.8 μW power consumption from 1 V supply and exhibited lowest PDP of 0.968 fJ. Moreover, the core circuit layout occupies only 183.3 μm 2 .
Frank G. Mbieda Ngomegni, Alain M. Dikandé, B. Z. Essimbi
Physica Scripta
Abstract The laser dynamics in inscription processes involving transparent media is carried out, by considering an optical field propagating in a transparent medium with Kerr nonlinearity. The study takes into account multi-photon absorption phenomena, as well as a possible modification of the material structure resulting in the generation of a plasma of nearly free electrons. The model is described by a complex Ginzburg–Landau equation governing the laser dynamics, in which an extra K th-order nonlinear term is induced by K -photon absorption processes. The model also takes into consideration the electron plasma generation via a linear term in the optical field. A global stability analysis of the system dynamics reveals a rich variety of fixed points consisting of no, one or two singular points in the amplitude-frequency plane. The modulational instability of plane waves gives rise to period-halving bifurcations in the continuous-wave amplitude growth rate, reminiscent of dominant multi-pulse structures in the nonlinear regime at large multi-photon absorption rate K . Pulses and multi-pulses are observed in numerical simulations of the nonlinear equations for the full system dynamics, the first structures are clearly associated with the case K = 2 whereas multi-pulse structures of increasing amplitudes and shorter perioids are dominant at larger values of K .
Alain M. Dikandé, J Voma Titafan, B. Z. Essimbi
Journal of Optics
Abstract The transition dynamics from continuous-wave to pulse regimes of operation for a generic model of passively mode-locked lasers with saturable absorbers, characterized by an active medium with non-Kerr nonlinearity, are investigated analytically and numerically. The system is described by a complex Ginzburg–Landau equation with a general m:n saturable nonlinearity (i.e <mml:math xmlns:mml="http://www.w3.org/1998/Math/MathML" overflow="scroll"> <mml:msup> <mml:mrow> <mml:mi>I</mml:mi> </mml:mrow> <mml:mrow> <mml:mi>m</mml:mi> </mml:mrow> </mml:msup> <mml:mrow> <mml:mo stretchy="true">/</mml:mo> </mml:mrow> <mml:msup> <mml:mrow> <mml:mo stretchy="false">(</mml:mo> <mml:mn>1</mml:mn> <mml:mo>+</mml:mo> <mml:mi mathvariant="normal">Γ</mml:mi> <mml:mspace width="0.25em"/> <mml:mi>I</mml:mi> <mml:mo stretchy="false">)</mml:mo> </mml:mrow> <mml:mrow> <mml:mi>n</mml:mi> </mml:mrow> </mml:msup> </mml:math> , where I is the field intensity and m and n are two positive numbers), coupled to a two-level gain equation. An analysis of stability of continuous waves, following the modulational instability approach, provides a global picture of the self-starting dynamics in the system. The analysis reveals two distinct routes depending on values of the couple ( m , n ), and on the dispersion regime: in the normal dispersion regime, when m = 2 and n is arbitrary, the self-starting requires positive values of the fast saturable absorber and nonlinearity coefficients, but negative values of these two parameters for the family with m = 0. However, when the spectral filter is negative, the laser can self-start for certain values of the input field and the nonlinearity saturation coefficient Γ. The present work provides a general map for the self-starting mechanisms of rare-earth doped figure-eight fiber lasers, as well as Kerr-lens mode-locked solid-state lasers.
E. L. Talon, Serge Gavin, Daniel Siemaszko, Frédéric Biya-Motto, B. Z. Essimbi, Mauro Carpita
This paper presents the design and implementation of a digital control system for modular multilevel converters, based on digital signal processors. To achieve higher system control reliability and multi-functionality, the proposed architecture has been built with an effective split of the control tasks involved between a master controller and six slave controllers, one for each of the six arms of the converter. The master controller handles energy flow within the converter and user communication using Ethernet and universal serial bus. Each slave controller handles capacitors voltages balancing within the arm. Intercommunication between the different boards is achieved mainly through optical fiber and inter-integrated circuit bus. Experiments have been carried out to verify the effectiveness of this architecture.
Roland Alima, Savério Morfu, Bertrand Bodo, P. Marquié, B. Z. Essimbi
HAL (Le Centre pour la Communication Scientifique Directe)
National audience
Yerima Klofaï, B. Z. Essimbi, D. Jäger
Physica Scripta
In this paper the electronic implementation of FitzHugh–Nagumo (F–N) neurons via monolithic microwave integrated circuits (MMIC) based upon a resonant tunneling diode (RTD) nonlinear transmission line (NLTL) using a coplanar waveguide (CPW) is considered. The goals are twofold. In the framework of electrical equivalent circuit emulating nonlinear active wave propagation effects, it is shown, on one hand, how different physical mechanisms are responsible for the time evolution of given input signals. A key result is that this medium supports stable and stationary pulse propagation that is only determined by the parameters of the RTD-NLTL and is independent of the boundary conditions. On the other hand, the influence of specific line elements on the output signal waveform is discussed in a most systematic manner. This leads, for the first time, to a more physical interpretation of the properties of the RTD-NLTL and, furthermore, to interesting technical applications at multi-GHz frequencies and on picosecond time scales. As a result, physically based ways are elucidated regarding how the technical design of those compact neuromorphic electrical circuits can be optimized by numerical simulations and performed using standard MMIC technologies.
Bertrand Bodo, Savério Morfu, P. Marquié, B. Z. Essimbi, Roland Alima
HAL (Le Centre pour la Communication Scientifique Directe)
National audience
Philippe Djondiné, Malek Ghanes, Jean‐Pierre Barbot, B. Z. Essimbi
HAL (Le Centre pour la Communication Scientifique Directe)
In this paper, the behavior analysis of two cells chopper connected to a nonlinear load is reported. Thus, this is done in order to highlight the way to chaos. Furthermore, throughout the study of these dynamical behaviors of this complex switched system some basic dynamical properties, such as Poincare section, first return map, bifurcation diagram, power spectrum, and strange attractor are investigated. The system examined in Matlab-Simulink. Analyses of simulation results show that this system has complex dynamics with some interesting characteristics.
Marie Danielle Fendji, Joseph Yves Effa, C. G. L. Tiofack, L. Kavitha, Alidou Mohamadou, B. Z. Essimbi
Journal of Computational and Theoretical Nanoscience
A nonlinear dynamic model which elucidate the mechanism of the internal motion occuring during the assembly of microtubules (MTs) is considered. The nonlinear space-time dynamics, defined in terms of celebrated ‘solitonic’ equations, brings indispensable tools for understanding, prediction and control of complex behaviors in both physical and life sciences. MTs is assumed to be a single longitudinal degree of freedom per tubulin dimer, and the motion equation is reduced to the discrete nonlinear Schr ¨ odinger equation. Exact solutions are investigated using the Jacobian elliptic fonctions approach. It is shown that such a nonlinear model can lead to the existence of kink solitons, breather as well as Jacobi solutions which can propagate along the microtubule outer surface, and the tubulin tail soliton collisions could serve as elementary computational gates that control cytoskeletal processes. We examine the stability of these solutions and found that the kink solution is stable with respect to small-amplitude fluctuations.
Yerima Klofaï, B. Z. Essimbi
Journal of Modern Physics
The characteristics of N-type accumulation-mode MOS (NMOS) varactors line periodically loaded with resonant tunneling diodes (RTDs) are used for soliton-like pulses generation and shaping. The problem of wide pulse breaking up into multiple pulses rather than a single is solved. Applying perturbative analysis, we show that the dynamics of the nonlinear transmission line (NLTL) is reduced to expanded Korteweg-de Vries (KdV) equation. Moreover, numerical integration of nonlinear differential and difference equations that result from the mathematical analysis of the line is discussed. As results, NLTL can simultaneously sharpen both leading and trailing of pulse edges and one could obtain a rising and sharpening step pulse.
Hala J. El‐Khozondar, Rifa J. El-Khozondra, Ahmed R.S. AL-Farra, B. Z. Essimbi
Optik
Janvier Fotsing, Emmanuel Tonyé, B. Z. Essimbi, Narcisse Talla, Jean-Paul Rudant
InTech eBooks
© 2012 Fotsing et al., licensee InTech. This is an open access chapter distributed under the terms of the Creative Commons Attribution License (http://creativecommons.org/licenses/by/3.0), which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. Contribution of SAR Radar Images for the Cartography: Case of Mangrove and Post Eruptive Regions
B. Z. Essimbi, D. Jäger
Journal of Infrared Millimeter and Terahertz Waves
A. D. Mengue, B. Z. Essimbi
Optical and Quantum Electronics
Yerima Klofaï, B. Z. Essimbi, D. Jäger
Physica Scripta
Pulse propagation on high-frequency dissipative nonlinear transmission lines (NLTLs)/resonant tunneling diode line cascaded maps is investigated for long-distance propagation of short pulses. Applying perturbative analysis, we show that the dynamics of each line is reduced to an expanded Korteweg–de Vries–Burgers equation. Moreover, it is found by computer experiments that the soliton developed in NLTLs experiences an exponential amplitude decay on the one hand and an exponential amplitude growth on the other. As a result, the behavior of a pulse in special electrical networks made of concatenated pieces of lines is closely similar to the transmission of information in optical/electrical communication systems.
B. Z. Essimbi, D. Jäger
Physica Scripta
We propose a method of generating electrical short pulses on a Schottky transmission line periodically loaded with resonant tunnelling diodes as a key device. Applying perturbative analysis, we show that the dynamics of the modified Schottky line is reduced to an expanded KdV–Burgers equation. The behaviour of the wave on the line is studied by computer experiment. As a result, the problem of a wide pulse breaking up into multiple pulses rather than a single pulse is solved.
Bernard Bodo, S. Morfu, P. Marquié, B. Z. Essimbi
Journal of Statistical Mechanics Theory and Experiment
We consider a sine–Gordon chain driven sinusoidally at one end. In the absence of noise, there exists a well known critical value of the amplitude beyond which breather modes can be generated via the phenomenon of supratransmission. We consider values of the driving amplitude below the critical amplitude such that no breather propagates in the medium. We show that noise induces breather generation with a given probability depending on the noise intensity. We also propose a bifurcation diagram which extends the supratransmission effect to a more realistic signal, namely a noisy sinusoidal excitation. We finally discuss some promising signal processing applications that can be developed by taking into account the contribution of noise in the media sharing this supratransmission phenomenon.
Joseph Yves Effa, B. Z. Essimbi, J.M. Ngundam
Communications in Nonlinear Science and Numerical Simulation
Joseph Yves Effa, B. Z. Essimbi, J.M. Ngundam
Nonlinear Dynamics
J.S. Armand Eyebe Fouda, B. Z. Essimbi, Mbane Biouele
Digital Signal Processing
B. Z. Essimbi, Timoléon Crépin Kofané
Physica Scripta
We discuss the coupling of stationary nonlinear excitations in an electrical lattice. Due to nonlinear interaction between the modes, we show within a quasi-discrete multiple scale approach that the physics of the network is described by two coupled nonlinear Schrodinger equations. Therefore, a novel class of lattice soliton is derived in the form of a coupled kink-soliton pair. Moreover, analytical results are checked by computer experiments.
B. Z. Essimbi, D. Jäger
Journal of Physics D Applied Physics
Nonlinear dispersive wave propagation along a bi-modal transmission line consisting of a bi-periodic arrangement of varactor diodes is examined. Localized solitary waves with eigenfrequencies in the gap of the linear spectrum of the line are observed experimentally for different modulation rate values of the input signal. With respect to the acoustic branch of the dispersion spectrum, these nonlinear waves exhibit monotonic profiles during their propagation along the line.
B. Z. Essimbi, D. Jäger
Current Applied Physics
B. Z. Essimbi, Timoléon Crépin Kofané, J.M. Ngundam
Physica Scripta
Gap solitons in the case of two mono-inductances lines coupled via linear capacitors are considered analytically by means of the method of perturbation combined with a rotating-wave approximation. We extend the local stability analysis at all points of the phase plane, and numerical experiments are undertaken to explore the space-time evolution of these waves.
Physica Scripta
We consider a model of an electric circuit, which consists of a primary monoinductance branch shunted (cell to cell) by a nonlinear capacitor and two alternate secondary inductances. The cw spectrum of this circuit exhibits two forbidden bands. By means of the method of multiple scales combined with a quasi-discreteness approximation, we show analytically in a unified way that, the system may support gap solitons, which have their frequencies of oscillation contained within these gaps, as well as intrinsic localized modes (with oscillation frequencies above all the phonon bands). Both kinds of excitations have zero group velocity.
B. Z. Essimbi, I. V. Barashenkov
Journal of the Physical Society of Japan
Nonlinear localized excitations in a bi-inductance electrical line are considered analytically by means of the method of multiple scales combined with a quasi-discreteness approximation. We show in a unified way that the system may support new types of gap solitons (with the frequency of oscillations lying in the gap of the continuous wave spectrum) and intrinsic localized modes (with the oscillation frequency being above all the phonon bands). Both kinds of excitations have zero group velocity.
B. Z. Essimbi, I. V. Barashenkov
Journal of the Physical Society of Japan
We study analytically by a quasi-discreteness approach, nonlinear localized excitations in a discrete electrical lattice which exhibits two natural gaps. We show that some new types of gap solitons as well as intrinsic localized modes, both waves having a zero-group velocity can exist in the line. These nonlinear excitations have also their frequency lying in the gaps of the continuous wave spectrum and oscillate with frequency being above all the phonon bands, respectively.
B. Z. Essimbi, Mane Mane, J.M. Ngundam
Journal of Physics D Applied Physics
Stationary solitary signals with eigenfrequencies in the gap of the linear spectrum are considered for a bi-inductance electrical transmission line. The evolution of these localized waves is studied in the phase plane and analytical expressions are obtained. Moreover, theoretical and numerical examinations of the stability of these nonlinear waves which appear as kink or antikink solitons, show that they are long-lived nonlinear excitations of the bi-inductance line.
B. Z. Essimbi, A A Zibi
Journal of Physics D Applied Physics
Stationary solitary signals with eigenfrequencies in a nonlinearity-induced gap of the linear spectrum are studied analytically on a nonlinear mono-inductance line. The stability of these nonlinear waves, which are kink or antikink solitons, are established theoretically as well as numerically. Computer experiments show how the electrical transmission line would behave in practice.
B. Z. Essimbi, L. Ambassa, Timoléon Crépin Kofané
Physica D Nonlinear Phenomena
B. Z. Essimbi, Alain M. Dikandé, Timoléon Crépin Kofané, A A Zibi
Physica Scripta
Gap Solitons (GS) are found in a model of non-linear transmission lines which simulates a Toda lattice. These gap solitons are asymmetric kinks which can propagate on a long distance without drastic shape distortions, and therefore are long-lived non-linear excitations of the LC Toda lattice.
B. Z. Essimbi, A A Zibi, Timoléon Crépin Kofané
Physica Scripta
We consider a nonlinear bi-inductance electrical transmission line which simulates a diatomic chain with non-linear cubic interactions. The linear spectrum of this model exhibits a gap which is proportional to the linear inductance difference. We analyse theoretically and numerically the coupled nonlinear excitations of such a bi-inductance line, which have a similar origin as the well-known gap solitons (GS) appearing in nonlinear systems with a spatial periodicity. Otherwise, these nonlinear modes are found in terms of asymmetric GS (kinks type) and are long-lived non-linear excitations.
Eba David Essebe, A. D. Mengue, B. Z. Essimbi
Research Square
Abstract In this paper a 6-D optoelectronic system consists of a resonant tunneling diode (RTD) driven by an optical injected semiconductor laser (LD) is reported. A stability analysis of the hybrid system is analytically and numerically performed and paramount role of the effective gain coefficient (EGC) is stuck out in the framework of new stability control. As a result, this parameter allows improving the accuracy of the stability study by circumscribing locked and unlocked regions. Besides, a narrow area of stability is pointed up within the sea of unstable points from which a complex fractal attractor so-called infinite-scroll attractor is highligted. Thereby, Simulink shows generation effectiveness of infinite-scroll attractor erratically interpersed by laminar phases. Also dynamics of Lyapunov exponents has confirmed that it refers to a strange fractal attractor. Moreover chaos control is structurally carried out by direct current (DC) polarisation.
A. Ngo Mouelas, Théophile Fonzin Fozin, Romanic Kengne, Jacques Kengne, Hilaire Bertrand Fotsin, B. Z. Essimbi
International Journal of Dynamics and Control
Nkongho Achere Akem, L. Akong Ngate, Alain M. Dikandé, B. Z. Essimbi
SN Applied Sciences
Nkongho Achere Akem, Alain M. Dikandé, B. Z. Essimbi
SN Applied Sciences
Abstract The leapfrogging dynamics of a pair of electrical solitons is investigated, by considering two capacitively coupled nonlinear transmission lines with and without intraline resistances. We discuss two distinct transmission line set-ups: in the first, we assume two RLC ladder lines with intraline varactors and a coupling linear capacitor, and in the second, we consider two capacitively coupled lossless lines with a varactor carrying impurity (imperfect diode) in one of the two interacting transmission lines. In the first context, we find that the soliton-pair leapfrogging mimics the motion of a damped harmonic oscillator, the frequency and damping coefficient of which are obtained analytically. Numerical simulations predict leapfrogging of the soliton pair when the differences in the initial values of the amplitude and phase are reasonably small, and the resistance is not too large. In the second context, leapfrogging occurs when the impurity rate is small enough and the differences in the initial values of the amplitude as well as phase are also small. As the impurity rate increases, the soliton signal in the imperfect line gets accelerated upon approaching the defective diode, causing only this specific soliton signal to move faster than its counterpart, leading to the suppression of leapfrogging.
B. Z. Essimbi, Andreas Stöhr, Irina Jäger, D. Jäger
Journal of Physics Communications
Abstract In this paper a coplanar waveguide (CPW) periodically loaded with resonant tunneling diodes (RTDs) and air bridges (AB) is presented as a travelling wave (TW) structure for modelling the FitzHugh-Nagumo (FHN) equation and emulating the behaviour of the nerve axon. Based upon an electrical equivalent circuit, the principle of operation is discussed in the context of a lumped-element circuital model being compared to a distributed structure. The phenomena of wave formation and propagation are studied by computer experiments of the underlying nonlinear ordinary difference-differential equations (ODEs) and that of the approximated model nonlinear partial differential equations (PDEs). A key achievement is that this medium supports stable propagating shock waves (kinks and antikinks) when effects of AB are neglected as well as stable traveling pulses only determined by the parameters of the circuit. As a result, compact electronic circuits with features of real neural systems are developed to be an experimental medium mimicking neural activity and to be applied in ultra-fast signal processing.
D. E. Essebe, A. D. Mengue, B. Z. Essimbi
Physica Scripta
Abstract In this paper the stochastic dynamics of an optically injected semiconductor laser (SCL) operating in the single mode are theoretically and numerically investigated in the framework of the Langevin approach. Novel modified analytical expressions for relative intensity noise (RIN) and frequency noise have been developed for both master laser and slave. The effective gain coefficient (EGC) parameter of this rate-equation model allows noise suppression of 65 dB to be achieved in addition to the diminution of RIN spectra achieved by classic decisive parameters. A modified Schawlow–Townes formula is also proposed for laser linewidth. Moreover the induced modulation of the FWHM by the mean EGC allows more significant reduction of the laser linewidth, unlike those of classic SCLs when the EGC is lower than 0.5, opening the route to the ideal laser linewidth, which is discussed. The impacts of linewidth enhancement factor, spontaneous emission factor and EGC are investigated in noise spectra around the threshold current.
Roland Alima, S. Morfu, P. Marquié, Bernard Bodo, B. Z. Essimbi
Chaos Solitons & Fractals
Duplex S. Mbieda Petmegni, Alain M. Dikandé, B. Z. Essimbi
Applied Physics B
Joseph Jean-Baptiste Mvogo Ahanda, Jean Bosco Mbede, Achille Melingui, B. Z. Essimbi
Robotica
SUMMARY This study derives a robust adaptive control of electrically driven robot manipulators using a support vector regression (SVR)-based command filtered adaptive backstepping approach. The robot system is supposed to be subject to model uncertainties, neglected dynamics, and external disturbances. The command filtered backstepping algorithm is extended to the case of the robot manipulators. A robust term is added to the common adaptive SVR algorithm, to mitigate the effects of the SVR approximation error in the path tracking performance. The stability analysis of the closed loop system using the Lyapunov theory permits to highlight adaptation laws and to prove that all the signals in the closed loop system are bounded. Simulations show the effectiveness of the proposed control strategy.
Roland Alima, Savério Morfu, P. Marquié, Bertrand Bodo, B. Z. Essimbi
HAL (Le Centre pour la Communication Scientifique Directe)
International audience
Yerima Klofaï, B. Z. Essimbi, D. Jäger
Physica Scripta
Analytic study and computer experiment investigations on a superconductive active transmission line using resonant tunneling diodes (RTDs) are discussed. It is shown, based on nonlinear wave propagation effects, that the line supports pulse propagation appearing as pairs of kink?antikink profiles. This behavior is due to compensation between the effects of amplification and dissipation along the network.
B. Z. Essimbi, D. Jäger
Physica Scripta
In this paper, the generation of short electrical pulses based on nonlinear active wave propagation effects along the resonant tunneling diode transmission line is studied. The principle of operation is discussed and it is shown by computer experiments that an input rectangular pulse as well as a sinusoidal input signal can be converted into a set of output spikes, suitable for A/D conversion at millimeter wave frequencies.
A. D. Mengue, B. Z. Essimbi
Nonlinear Dynamics
A. D. Mengue, B. Z. Essimbi
Physica Scripta
In this paper, we consider the modified single-mode rate equations for a semiconductor laser (SCL) subjected to optical injection. In addition to the well-known control parameters of this kind of system, a new control one, namely the effective gain coefficient (EGC), interferes especially with its nonlinear dynamics. A stability analysis reveals that the unstable locking regions are drastically influenced by EGC, and this can contribute towards improving its accuracy. The generation and destruction of chaotic states through the period-doubling bifurcation route lead to the strengthening of these states. Furthermore, various phenomena such as intermittency bifurcation around the period windows, the general behavior of the SCL systems at the onset of the quasi-periodic regime near the coherence collapse regime and the nonlinear dynamic route sequences to the limit value of the EGC were studied with regard to the impact of this new control parameter.
A. D. Mengue, B. Z. Essimbi
Chaos An Interdisciplinary Journal of Nonlinear Science
This paper presents the nonlinear dynamics and bifurcations of optically injected semiconductor lasers in the frame of relative high injection strength. The behavior of the system is explored by means of bifurcation diagrams; however, the exact nature of the involved dynamics is well described by a detailed study of the dynamics evolutions as a function of the effective gain coefficient. As results, we notice the different types of symmetry chaotic attractors with the riddled basins, supercritical pitchfork and Hopf bifurcations, crisis of attractors, instability of chaos, symmetry breaking and restoring bifurcations, and the phenomena of the bursting behavior as well as two connected parts of the same chaotic attractor which merge in a periodic orbit.
B. Z. Essimbi, I. V. Barashenkov
Journal of Physics D Applied Physics
A quasi-discreteness approximation is employed to study analytically spatially localized voltage oscillations in a discrete electrical lattice. We show that the system may support new types of gap solitons as well as upper cut-off solitons (intrinsic localized modes), both nonlinear localized modes having a zero group velocity.
B. Z. Essimbi, A A Zibi, A. Zame, Timoléon Crépin Kofané
Journal of the Physical Society of Japan
Soliton-like excitations with frequencies in the gap of a linear spectrum ar considered for a new type of nonlinear LC circuit recently introduced by S. Ishiwata et al . [J. Phys. Soc. Jpn. 59 (1990) 1163]. A nonlinear capacitor whose capacitance depends on the square root of the voltage in the shunt branch is composed of two diodes connected in series but inversely with each other. Numerical results are obtained which show the existence of a new class of localized solitary signals.
B. Z. Essimbi, Alain M. Dikandé, Timoléon Crépin Kofané, A A Zibi
Journal of the Physical Society of Japan
A new class of localized solitary signals is investigated on a coupled nonlinear transmission line, which consists of two LC ladder lines connected by intermediary capacitors. Actually, these localized solitary excitations correspond to configurations where electric signal voltages on nearest-neighbour electric cells of each LC ladder line oscillate out of phases with each other, at the same frequency. Thus, it is found that they are stationary nonlinear asymmetric waves, whose amplitudes and widths depend on characteristic parameters of the circuit. The explicit envelope functions which are appropriate for coupled system with finite lengths are also found.
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