Sebastian Wieczorek - Academia.edu (original) (raw)
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Papers by Sebastian Wieczorek
We show how bifurcation theory and experimental measurements can be used hand-in-hand to analyse ... more We show how bifurcation theory and experimental measurements can be used hand-in-hand to analyse transitions to complicated dynamics in a semiconductor laser subject to optical injection. By a direct comparison of theoretical and experimental optical spectra we identify and explain the underlying dynamics in phase space. This is demonstrated with four distinct bifurcation transitions, including a transition near a saddle-node Hopf point and an intermittent transition to chaos.
We theoretically study analytic-phase synchronization in strongly-competing oscillator systems. U... more We theoretically study analytic-phase synchronization in strongly-competing oscillator systems. Using the example of composite-cavity modes coupled via a class-B laser active medium, we discover that inherent chaotic phase synchronization can arise concurrently at two different chaotic attractors, leading to bistable phase-synchronized solutions. In our example, the underlying mechanism for bistability and inherent phase synchronization is population pulsation within the active medium.
The 17th Annual Meeting of the Ieeelasers and Electro Optics Society 2004 Leos 2004, Dec 11, 2004
Tipping points associated with bifurcations (B-tipping) or induced by noise (N-tipping) are recog... more Tipping points associated with bifurcations (B-tipping) or induced by noise (N-tipping) are recognized mechanisms that may potentially lead to sudden climate change. We focus here a novel class of tipping points, where a sufficiently rapid change to an input or parameter of a system may cause the system to "tip" or move away from a branch of attractors. Such rate-dependent
Physical Review a Atomic Molecular and Optical Physics, 2004
The paper presents a theoretical study of synchronization between two coupled lasers. A theory va... more The paper presents a theoretical study of synchronization between two coupled lasers. A theory valid for arbitrary coupling between lasers is used. Its key feature is that the laser field is decomposed in terms of the composite-cavity modes reflecting the spatial field dependence over the entire coupled-laser system. The ensuing multimode equations are reduced to class-B, and further to class-A equations which resemble competing species equations. Bifurcation analysis, supported by insight provided by analytical solutions, is used to investigate influences of pump, carrier decay rate, polarization decay rate, and coupling mirror losses on synchronization between lasers. Population pulsation is found to be an essential mode competition mechanism responsible for bistability in the synchronized solutions. Finally, we discovered that the mechanism leading to laser synchronization changes from strong composite-cavity mode competition in class-A regime to frequency locking of composite-cavity modes in class-B regime.
We found very good agreement between theoretical and experimental bifurcation diagrams of an opti... more We found very good agreement between theoretical and experimental bifurcation diagrams of an optically injected diode laser. Identifying regions of various dynamics opens new possibilities for applying this system to all optical signal manipulation.
... surface of the nanowires is considerable, particularly with regard to high energy photons ...... more ... surface of the nanowires is considerable, particularly with regard to high energy photons ... FDTD simulation of metallic gratings for enhancement of electromagnetic field by surface plasmon resonance. ... both gold and silver metals arranged in either square or triangular lattices was ...
2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, 2006
Experimentally observed 5-fold increase in the modulation bandwidth of strongly injected VCSELs i... more Experimentally observed 5-fold increase in the modulation bandwidth of strongly injected VCSELs is explained to arise from injection-induced population pulsation. The injected-laser rate-equations reproduce the relevant aspects of modulation experiments on different VCSEL structures.
MRS Proceedings, 2004
Materials studies of high Al-content (&am... more Materials studies of high Al-content (> 30%) AlGaN epilayers and the performance of AlGaN-based LEDs with emission wavelengths shorter than 300 nm are reported. N-type AlGaN films with Al compositions greater than 30% reveal a reduction in conductivity with increasing Al composition. The reduction of threading dislocation density from the 1-5 x10¹° cm² range to the 6-9 x 10cm² range
Semiconductor Lasers and Laser Dynamics IV, 2010
We present an analysis of a semiconductor laser subject to filtered optical feedback from two fil... more We present an analysis of a semiconductor laser subject to filtered optical feedback from two filtering elements (2FOF). The motivation for this study comes from applications where two filters are used to control and stabilise the laser output. Compared to a laser with a single filtered optical feedback loop, the introduction of the second filter significantly influences the structure of the basic continuous-wave solutions, which are also known as external filtered modes (EFMs). We compute and represent the EFMs of the underlying delay differential equation model as surfaces in the space of frequency ω s and inversion level N s of the laser, and feedback phase difference dC p . The quantity dC p is a key parameter since it is associated with interference between the two filter fields and, hence, controls the effective feedback strength. We further show how the EFM surface in (ω s , dC p , N s )-space changes upon variation of other filter parameters, in particular, the two delay times. Overall, the investigation of the EFM-surface provides a geometric approach to the multi-parameter analysis of the 2FOF laser, which allows for comprehensive insight into the solution structure and dynamics of the system.
Physical Review E, 2010
The stability of two semiconductor lasers that are spatially separated by a passive resonator is ... more The stability of two semiconductor lasers that are spatially separated by a passive resonator is analyzed using the composite-cavity mode approach. We study the nonlinear interactions of three composite-cavity modes and identify regions of in-phase and out-of-phase laser locking in the parameter plane of the transmission coefficients of the coupling mirrors and the laser length difference. Bifurcation analysis shows that
Optics Communications, 2005
Optics Communications, 2003
Physical review. E, Statistical, nonlinear, and soft matter physics, 2002
We demonstrate unprecedented agreement between a theoretical two-dimensional bifurcation diagram ... more We demonstrate unprecedented agreement between a theoretical two-dimensional bifurcation diagram and the corresponding experimental stability map of an optically injected semiconductor laser over a large range of relevant injection parameter values. The bifurcation diagram encompasses both local and global bifurcations mapping out regions of regular, chaotic, and multistable behavior in considerable detail. This demonstrates the power of dynamical systems modeling for the quantitative prediction of nonlinear dynamics and chaos of semiconductor lasers.
Physical review. E, Statistical, nonlinear, and soft matter physics, 2001
We present a theoretical study of unnested period-doubling islands in three-dimensional rate equa... more We present a theoretical study of unnested period-doubling islands in three-dimensional rate equations modeling a semiconductor laser subject to external optical injection. In this phenomenon successive curves of period doublings are not arranged in nicely nested islands, but intersect each other. This overall structure is globally organized by several codimension-2 bifurcations. As a consequence, the chaotic region existing inside an unnested island of period doublings can be entered not only via a period-doubling cascade but also via the breakup of a torus, and even via the sudden appearance of a chaotic attractor. In order to fully understand these different chaotic transitions we reveal underlying global bifurcations and we show how they are connected to codimension-2 bifurcation points. Unnested islands of period doublings appear to be generic and hence must be expected in a large class of dynamical systems.
CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009
In this paper, we address the issue by using the composite cavity mode approach, the entire laser... more In this paper, we address the issue by using the composite cavity mode approach, the entire laser structure is modelled as a single device with several composite cavity modes. The frequencies of these modes, as well as their gain and coupling coefficients, are calculated explicitly and depend on the geometry of the entire laser device. This allows for arbitrary coupling
We show how bifurcation theory and experimental measurements can be used hand-in-hand to analyse ... more We show how bifurcation theory and experimental measurements can be used hand-in-hand to analyse transitions to complicated dynamics in a semiconductor laser subject to optical injection. By a direct comparison of theoretical and experimental optical spectra we identify and explain the underlying dynamics in phase space. This is demonstrated with four distinct bifurcation transitions, including a transition near a saddle-node Hopf point and an intermittent transition to chaos.
We theoretically study analytic-phase synchronization in strongly-competing oscillator systems. U... more We theoretically study analytic-phase synchronization in strongly-competing oscillator systems. Using the example of composite-cavity modes coupled via a class-B laser active medium, we discover that inherent chaotic phase synchronization can arise concurrently at two different chaotic attractors, leading to bistable phase-synchronized solutions. In our example, the underlying mechanism for bistability and inherent phase synchronization is population pulsation within the active medium.
The 17th Annual Meeting of the Ieeelasers and Electro Optics Society 2004 Leos 2004, Dec 11, 2004
Tipping points associated with bifurcations (B-tipping) or induced by noise (N-tipping) are recog... more Tipping points associated with bifurcations (B-tipping) or induced by noise (N-tipping) are recognized mechanisms that may potentially lead to sudden climate change. We focus here a novel class of tipping points, where a sufficiently rapid change to an input or parameter of a system may cause the system to "tip" or move away from a branch of attractors. Such rate-dependent
Physical Review a Atomic Molecular and Optical Physics, 2004
The paper presents a theoretical study of synchronization between two coupled lasers. A theory va... more The paper presents a theoretical study of synchronization between two coupled lasers. A theory valid for arbitrary coupling between lasers is used. Its key feature is that the laser field is decomposed in terms of the composite-cavity modes reflecting the spatial field dependence over the entire coupled-laser system. The ensuing multimode equations are reduced to class-B, and further to class-A equations which resemble competing species equations. Bifurcation analysis, supported by insight provided by analytical solutions, is used to investigate influences of pump, carrier decay rate, polarization decay rate, and coupling mirror losses on synchronization between lasers. Population pulsation is found to be an essential mode competition mechanism responsible for bistability in the synchronized solutions. Finally, we discovered that the mechanism leading to laser synchronization changes from strong composite-cavity mode competition in class-A regime to frequency locking of composite-cavity modes in class-B regime.
We found very good agreement between theoretical and experimental bifurcation diagrams of an opti... more We found very good agreement between theoretical and experimental bifurcation diagrams of an optically injected diode laser. Identifying regions of various dynamics opens new possibilities for applying this system to all optical signal manipulation.
... surface of the nanowires is considerable, particularly with regard to high energy photons ...... more ... surface of the nanowires is considerable, particularly with regard to high energy photons ... FDTD simulation of metallic gratings for enhancement of electromagnetic field by surface plasmon resonance. ... both gold and silver metals arranged in either square or triangular lattices was ...
2006 Conference on Lasers and Electro-Optics and 2006 Quantum Electronics and Laser Science Conference, 2006
Experimentally observed 5-fold increase in the modulation bandwidth of strongly injected VCSELs i... more Experimentally observed 5-fold increase in the modulation bandwidth of strongly injected VCSELs is explained to arise from injection-induced population pulsation. The injected-laser rate-equations reproduce the relevant aspects of modulation experiments on different VCSEL structures.
MRS Proceedings, 2004
Materials studies of high Al-content (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;am... more Materials studies of high Al-content (&amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;amp;gt; 30%) AlGaN epilayers and the performance of AlGaN-based LEDs with emission wavelengths shorter than 300 nm are reported. N-type AlGaN films with Al compositions greater than 30% reveal a reduction in conductivity with increasing Al composition. The reduction of threading dislocation density from the 1-5 x10¹° cm² range to the 6-9 x 10cm² range
Semiconductor Lasers and Laser Dynamics IV, 2010
We present an analysis of a semiconductor laser subject to filtered optical feedback from two fil... more We present an analysis of a semiconductor laser subject to filtered optical feedback from two filtering elements (2FOF). The motivation for this study comes from applications where two filters are used to control and stabilise the laser output. Compared to a laser with a single filtered optical feedback loop, the introduction of the second filter significantly influences the structure of the basic continuous-wave solutions, which are also known as external filtered modes (EFMs). We compute and represent the EFMs of the underlying delay differential equation model as surfaces in the space of frequency ω s and inversion level N s of the laser, and feedback phase difference dC p . The quantity dC p is a key parameter since it is associated with interference between the two filter fields and, hence, controls the effective feedback strength. We further show how the EFM surface in (ω s , dC p , N s )-space changes upon variation of other filter parameters, in particular, the two delay times. Overall, the investigation of the EFM-surface provides a geometric approach to the multi-parameter analysis of the 2FOF laser, which allows for comprehensive insight into the solution structure and dynamics of the system.
Physical Review E, 2010
The stability of two semiconductor lasers that are spatially separated by a passive resonator is ... more The stability of two semiconductor lasers that are spatially separated by a passive resonator is analyzed using the composite-cavity mode approach. We study the nonlinear interactions of three composite-cavity modes and identify regions of in-phase and out-of-phase laser locking in the parameter plane of the transmission coefficients of the coupling mirrors and the laser length difference. Bifurcation analysis shows that
Optics Communications, 2005
Optics Communications, 2003
Physical review. E, Statistical, nonlinear, and soft matter physics, 2002
We demonstrate unprecedented agreement between a theoretical two-dimensional bifurcation diagram ... more We demonstrate unprecedented agreement between a theoretical two-dimensional bifurcation diagram and the corresponding experimental stability map of an optically injected semiconductor laser over a large range of relevant injection parameter values. The bifurcation diagram encompasses both local and global bifurcations mapping out regions of regular, chaotic, and multistable behavior in considerable detail. This demonstrates the power of dynamical systems modeling for the quantitative prediction of nonlinear dynamics and chaos of semiconductor lasers.
Physical review. E, Statistical, nonlinear, and soft matter physics, 2001
We present a theoretical study of unnested period-doubling islands in three-dimensional rate equa... more We present a theoretical study of unnested period-doubling islands in three-dimensional rate equations modeling a semiconductor laser subject to external optical injection. In this phenomenon successive curves of period doublings are not arranged in nicely nested islands, but intersect each other. This overall structure is globally organized by several codimension-2 bifurcations. As a consequence, the chaotic region existing inside an unnested island of period doublings can be entered not only via a period-doubling cascade but also via the breakup of a torus, and even via the sudden appearance of a chaotic attractor. In order to fully understand these different chaotic transitions we reveal underlying global bifurcations and we show how they are connected to codimension-2 bifurcation points. Unnested islands of period doublings appear to be generic and hence must be expected in a large class of dynamical systems.
CLEO/Europe - EQEC 2009 - European Conference on Lasers and Electro-Optics and the European Quantum Electronics Conference, 2009
In this paper, we address the issue by using the composite cavity mode approach, the entire laser... more In this paper, we address the issue by using the composite cavity mode approach, the entire laser structure is modelled as a single device with several composite cavity modes. The frequencies of these modes, as well as their gain and coupling coefficients, are calculated explicitly and depend on the geometry of the entire laser device. This allows for arbitrary coupling