The Experts below are selected from a list of 132 Experts worldwide ranked by ideXlab platform
Claudio R Mirasso - One of the best experts on this subject based on the ideXlab platform.
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
European Quantum Electronics Conference, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:The control of semiconductor exhibiting dynamical instabilities has received considerable attention during recent years. Our purpose in this work is to prevent periodic or chaotic oscillations in a semiconductor laser subject to conventional optical Feedback (COF) by stabilizing it in a CW regime. We propose the use of a filtered optical Feedback (FOF) from an external mirror in one of the external Branches. Using FOF rather than COF the control of the system is easier and more effective. The proposed device (Fig. 1, left) consists of a semiconductor laser coupled to the two external reflectors. One Branch is the conventional Feedback Branch (CFB) and the other is the filtered Feedback Branch (FFB). The frequency dependent reflectivity in the FFB is described by a Lorenzian function [1]. The laser dynamics is analyzed in the framework of the extended Lang-Kobayashi rate equations [2] for the complex field amplitudes E(t), F(t) and excess carrier density N(t).
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
Optics Express, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical Feedback by means of a second filtered Feedback Branch. We give an overview of the analytical solutions of the double cavity Feedback and show numerically that the region of stabilization is much larger when using a second Branch with filtered Feedback than when using a conventional Feedback one.
I V Ermakov - One of the best experts on this subject based on the ideXlab platform.
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
European Quantum Electronics Conference, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:The control of semiconductor exhibiting dynamical instabilities has received considerable attention during recent years. Our purpose in this work is to prevent periodic or chaotic oscillations in a semiconductor laser subject to conventional optical Feedback (COF) by stabilizing it in a CW regime. We propose the use of a filtered optical Feedback (FOF) from an external mirror in one of the external Branches. Using FOF rather than COF the control of the system is easier and more effective. The proposed device (Fig. 1, left) consists of a semiconductor laser coupled to the two external reflectors. One Branch is the conventional Feedback Branch (CFB) and the other is the filtered Feedback Branch (FFB). The frequency dependent reflectivity in the FFB is described by a Lorenzian function [1]. The laser dynamics is analyzed in the framework of the extended Lang-Kobayashi rate equations [2] for the complex field amplitudes E(t), F(t) and excess carrier density N(t).
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
Optics Express, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical Feedback by means of a second filtered Feedback Branch. We give an overview of the analytical solutions of the double cavity Feedback and show numerically that the region of stabilization is much larger when using a second Branch with filtered Feedback than when using a conventional Feedback one.
V Z Tronciu - One of the best experts on this subject based on the ideXlab platform.
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
European Quantum Electronics Conference, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:The control of semiconductor exhibiting dynamical instabilities has received considerable attention during recent years. Our purpose in this work is to prevent periodic or chaotic oscillations in a semiconductor laser subject to conventional optical Feedback (COF) by stabilizing it in a CW regime. We propose the use of a filtered optical Feedback (FOF) from an external mirror in one of the external Branches. Using FOF rather than COF the control of the system is easier and more effective. The proposed device (Fig. 1, left) consists of a semiconductor laser coupled to the two external reflectors. One Branch is the conventional Feedback Branch (CFB) and the other is the filtered Feedback Branch (FFB). The frequency dependent reflectivity in the FFB is described by a Lorenzian function [1]. The laser dynamics is analyzed in the framework of the extended Lang-Kobayashi rate equations [2] for the complex field amplitudes E(t), F(t) and excess carrier density N(t).
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
Optics Express, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical Feedback by means of a second filtered Feedback Branch. We give an overview of the analytical solutions of the double cavity Feedback and show numerically that the region of stabilization is much larger when using a second Branch with filtered Feedback than when using a conventional Feedback one.
Pere Colet - One of the best experts on this subject based on the ideXlab platform.
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
European Quantum Electronics Conference, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:The control of semiconductor exhibiting dynamical instabilities has received considerable attention during recent years. Our purpose in this work is to prevent periodic or chaotic oscillations in a semiconductor laser subject to conventional optical Feedback (COF) by stabilizing it in a CW regime. We propose the use of a filtered optical Feedback (FOF) from an external mirror in one of the external Branches. Using FOF rather than COF the control of the system is easier and more effective. The proposed device (Fig. 1, left) consists of a semiconductor laser coupled to the two external reflectors. One Branch is the conventional Feedback Branch (CFB) and the other is the filtered Feedback Branch (FFB). The frequency dependent reflectivity in the FFB is described by a Lorenzian function [1]. The laser dynamics is analyzed in the framework of the extended Lang-Kobayashi rate equations [2] for the complex field amplitudes E(t), F(t) and excess carrier density N(t).
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controlling the unstable emission of a semiconductor laser subject to conventional optical Feedback with a filtered Feedback Branch
Optics Express, 2009Co-Authors: I V Ermakov, V Z Tronciu, Pere Colet, Claudio R MirassoAbstract:We show the advantages of controlling the unstable dynamics of a semiconductor laser subject to conventional optical Feedback by means of a second filtered Feedback Branch. We give an overview of the analytical solutions of the double cavity Feedback and show numerically that the region of stabilization is much larger when using a second Branch with filtered Feedback than when using a conventional Feedback one.
Riccardo Barbieri - One of the best experts on this subject based on the ideXlab platform.
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Dynamic Assessment of Baroreflex Control of Heart Rate During Induction of Propofol Anesthesia Using a Point Process Method
Annals of Biomedical Engineering, 2011Co-Authors: Zhe Chen, Patrick L. Purdon, Grace Harrell, Eric T. Pierce, John Walsh, Emery N. Brown, Riccardo BarbieriAbstract:In this article, we present a point process method to assess dynamic baroreflex sensitivity (BRS) by estimating the baroreflex gain as focal component of a simplified closed-loop model of the cardiovascular system. Specifically, an inverse Gaussian probability distribution is used to model the heartbeat interval, whereas the instantaneous mean is identified by linear and bilinear bivariate regressions on both the previous R−R intervals (RR) and blood pressure (BP) beat-to-beat measures. The instantaneous baroreflex gain is estimated as the Feedback Branch of the loop with a point-process filter, while the $$\hbox{RR}\to\hbox{BP}$$ feedforward transfer function representing heart contractility and vasculature effects is simultaneously estimated by a recursive least-squares filter. These two closed-loop gains provide a direct assessment of baroreflex control of heart rate (HR). In addition, the dynamic coherence, cross bispectrum, and their power ratio can also be estimated. All statistical indices provide a valuable quantitative assessment of the interaction between heartbeat dynamics and hemodynamics. To illustrate the application, we have applied the proposed point process model to experimental recordings from 11 healthy subjects in order to monitor cardiovascular regulation under propofol anesthesia. We present quantitative results during transient periods, as well as statistical analyses on steady-state epochs before and after propofol administration. Our findings validate the ability of the algorithm to provide a reliable and fast-tracking assessment of BRS, and show a clear overall reduction in baroreflex gain from the baseline period to the start of propofol anesthesia, confirming that instantaneous evaluation of arterial baroreflex control of HR may yield important implications in clinical practice, particularly during anesthesia and in postoperative care.
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Dynamic Assessment of Baroreflex Control of Heart Rate During Induction of Propofol Anesthesia Using a Point Process Method
Annals of Biomedical Engineering, 2010Co-Authors: Zhe Chen, Patrick L. Purdon, Grace Harrell, Eric T. Pierce, Emery N. Brown, John L. Walsh, Riccardo BarbieriAbstract:In this paper, we present a point process method to assess dynamic baroreflex sensitivity by estimating the baroreflex gain as focal component of a simplified closed-loop model of the cardiovascular system. Specifically, an inverse Gaussian probability distribution is used to model the heartbeat interval, whereas the instantaneous mean is identified by linear and bilinear bivariate regressions on both the previous R-R intervals (RR) and blood pressure (BP) beat-to-beat measures. The instantaneous baroreflex gain is estimated as the Feedback Branch of the loop with a point-process filter, while the RR→BP feedforward transfer function representing heart contractility and vasculature effects is simultaneously estimated by a recursive least-squares (RLS) filter. These two closed-loop gains provide a direct assessment of baroreflex control of heart rate. In addition, the dynamic coherence, cross-bispectrum, and their power ratio can also be estimated. All statistical indices provide a valuable quantitative assessment of the interaction between heartbeat dynamics and hemodynamics. To illustrate the application, we have applied the proposed point process model to experimental recordings from eleven healthy subjects in order to monitor cardiovascular regulation under propofol anesthesia. We present quantitative results during transient periods, as well as statistical analyses on steady state epochs before and after propofol administration. Our findings validate the ability of the algorithm to provide a reliable and fast-tracking assessment of baroreflex sensitivity (BRS), and show a clear overall reduction in baroreflex gain from the baseline period to the start of propofol anesthesia, confirming that instantaneous evaluation of arterial baroreflex control of heart rate may yield important implications in clinical practice, particularly during anesthesia and in postoperative care.
