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89 results on '"Kovalev, Anton V."'

1. Noise-induced broadening of a quantum-dash laser optical frequency comb

Author

Borodkin, Aleksei I., Kovalev, Anton V., Giudici, Massimo, Huyet, Guillaume, Ramdane, Abderrahim, Marconi, Mathias, and Viktorov, Evgeny A.

Subjects
Physics - Optics
Abstract

Single-section quantum dash semiconductor lasers have attracted much attention as an integrated and simple platform for the generation of THz-wide and flat optical frequency combs in the telecom C-band. In this work, we present an experimental method allowing to increase the spectral width of the laser comb by the injection of a broadband optical noise from an external semiconductor optical amplifier that is spectrally overlapped with the quantum dash laser comb. The noise injection induces an amplification of the side modes of the laser comb which acquire a fixed phase relationship with the central modes of the comb. We demonstrate a broadening of the laser comb by a factor of two via this technique., Comment: 4 pages, 4 figures

Published
2023
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2. Resonances between fundamental frequencies for lasers with large delayed feedbacks

Author

Kovalev, Anton V., Islam, Md Shariful, Locquet, A., Citrin, D. S., Viktorov, Evgeny A., and Erneux, Thomas

Subjects
Physics - Optics, Nonlinear Sciences - Pattern Formation and Solitons
Abstract

High-order frequency locking phenomena were recently observed using semiconductor lasers subject to large delayed feedbacks [B. Tykalewicz, et al., Opt. Express 24, 4239 (2016); B. Kelleher, et al., Chaos 27, 114325 (2017)]. Specifically, the relaxation oscillation (RO) frequency and a harmonic of the feedback-loop round-trip frequency coincided with the ratios 1:5 to 1:11. By analyzing the rate equations for the dynamical degrees of freedom in a laser subject to a delayed optoelectronic feedback, we show that the onset of a two-frequency train of pulses occurs through two successive bifurcations. While the first bifurcation is a primary Hopf bifurcation to the ROs, a secondary Hopf bifurcation leads to a two-frequency regime where a low frequency, proportional to the inverse of the delay, is resonant with the RO frequency. We derive an amplitude equation, valid near the first Hopf bifurcation point, and numerically observe the frequency locking. We mathematically explain this phenomenon by formulating a closed system of ordinary differential equations from our amplitude equation. Our findings motivate new experiments with particular attention to the first two bifurcations. We observe experimentally (1) the frequency locking phenomenon as we pass the secondary bifurcation point, and (2) the nearly constant slow period as the two-frequency oscillations grow in amplitude. Our results analytically confirm previous observations of frequency locking phenomena for lasers subject to a delayed optical feedback., Comment: 13 pages, 10 figures

Published
2019
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3. Dynamics of a class A nonlinear mirror mode-locked laser

Author

Vladimirov, Andrei G., Kovalev, Anton V., Viktorov, Evgeny A., Rebrova, Natalia, and Huyet, Guillaume

Subjects
Physics - Optics, Nonlinear Sciences - Pattern Formation and Solitons
Abstract

Using a delay differential equation model we study theoretically the dynamics of a unidirectional class-A ring laser with a nonlinear amplifying loop mirror. We perform linear stability analysis of the CW regimes in the large delay limit and demonstrate that these regimes can be destabilized via modulational and Turing-type instabilities, as well as by an instability leading to the appearance of square-waves. We investigate the formation of square-waves and mode-locked pulses in the system. We show that mode-locked pulses are asymmetric with exponential decay of the trailing edge in positive time and faster-than-exponential (super-exponential) decay of the leading edge in negative time. We discuss asymmetric interaction of these pulses leading to a formation of harmonic mode-locked regimes., Comment: 9 pages

Published
2019
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4. Class-A mode-locked lasers: fundamental solutions

Author

Kovalev, Anton V. and Viktorov, Evgeny A.

Subjects
Physics - Optics
Abstract

We consider a delay differential equation (DDE) model for mode-locked operation in class-A semiconductor lasers containing both gain and absorber sections. The material processes are adiabatically eliminated as these are considered fast in comparison to the delay time for a long cavity device. We determine the steady states and analyze their bifurcations using DDE-BIFTOOL [K. Engelborghs, T. Luzyanina, and D. Roose, ACM Trans. Math. Softw. 28, 1 (2002)]. Multiple forms of coexistence, transformation and hysteretic behavior of stable steady states and fundamental periodic regimes are discussed in bifurcation diagrams., Comment: 6 pages, 8 figures, accepted in 'Chaos'

Published
2017
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5. Mode-locked laser with multiple timescales in a microresonator-based nested cavity

Author

Aadhi, A., primary, Alamgir, Imtiaz, additional, Di Lauro, Luigi, additional, Fischer, Bennet, additional, Perron, Nicolas, additional, Dmitriev, Pavel, additional, Mazoukh, Celine, additional, Roztocki, Piotr, additional, Rimoldi, Cristina, additional, Chemnitz, Mario, additional, Eshaghi, Armaghan, additional, Viktorov, Evgeny A., additional, Kovalev, Anton V., additional, Little, Brent E., additional, Chu, Sai T., additional, Moss, David J., additional, and Morandotti, Roberto, additional

Published
2024
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9. Short-delayed-feedback semiconductor lasers

Author

Kovalev, Anton V., Viktorov, Evgeny, Erneux, Thomas, Kovalev, Anton V., Viktorov, Evgeny, and Erneux, Thomas

Abstract

We consider the laser rate equations describing the evolution of a semiconductor laser subject to an optoelectronic feedback. We concentrate on the first Hopf bifurcation induced by a short delay and develop an asymptotic theory where the delayed variable is Taylor expanded. We determine a nearly vertical branch of strongly nonlinear oscillations and derive ordinary differential equations that capture the bifurcation properties of the original delay differential equations. An unexpected result is the need for Taylor expanding the delayed variable up to third order rather than first order. We discuss recent laser experiments where sustained oscillations have been clearly observed with a short-delayed feedback., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2021

11. Effect of feedback on multi-section semiconductor swept-source laser for OCT applications

Author

Roy, Aritra, primary, Patra, Saroj Kanta, additional, Slepneva, Svetlana, additional, Kovalev, Anton V., additional, Grigorenko, Konstantin, additional, Rebrova, Natalia, additional, Verschelde, Alexis, additional, Roche, Amy, additional, Marconi, Mathias, additional, Giudici, Massimo, additional, Viktorov, Evgeny, additional, Piwonski, Tomasz, additional, and Huyet, Guillaume, additional

Published
2021
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12. Bifurcation structure of a swept source laser

Author

Kovalev, Anton V., Dmitriev, Pavel S., Vladimirov, Andrei G., Pimenov, Alexander, Huyet, Guillaume, and Viktorov, Evgeniy A.

Subjects
bifurcation structure, Frequency swept souce, 02.30.Ks, 42.55.Ah, 42.55.Px, Physics::Optics, 42.65.Sf, 42.60.Mi
Abstract

We numerically analyze a delay differential equation model of a short-cavity semiconductor laser with an intracavity frequency swept filter and reveal a complex bifurcation structure responsible for the asymmetry of the output characteristics of this laser. We show that depending on the direction of the frequency sweep of a narrowband filter, there exist two bursting cycles determined by different parts of a continuous-wave solutions branch.

Published
2020
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13. Pulse dynamics in SESAM-free electrically pumped VECSEL

Author

Chichkov, Nikolai B., Yadav, Amit, Kovalev, Anton V., Smirnov, Semyon V., Herper, Markus, Fedorova, Ksenia A., Viktorov, Evgeny A., Rafailov, Edik U., Chichkov, Nikolai B., Yadav, Amit, Kovalev, Anton V., Smirnov, Semyon V., Herper, Markus, Fedorova, Ksenia A., Viktorov, Evgeny A., and Rafailov, Edik U.

Abstract

Self-starting pulsed operation in an electrically pumped (EP) vertical-external-cavity surface-emitting-laser (VECSEL) without intracavity saturable absorber is demonstrated. A linear hemispherical cavity design, consisting of the EP-VECSEL chip and a 10% output-coupler, is used to obtain picosecond output pulses with energies of 2.8 pJ and pulse widths of 130 ps at a repetition rate of 1.97 GHz. A complete experimental analysis of the generated output pulse train and of the transition from continuous-wave to pulsed operation is presented. Numerical simulations based on a delay-differential-equation (DDE) model of mode-locked semiconductor lasers are used to reproduce the pulse dynamics and identify different laser operation regimes. From this, the measured single pulse operation is attributed to FM-type mode-locking. The pulse formation is explained by strong amplitude-phase coupling and spectral filtering inside the EP-VECSEL.

Published
2020

14. Non-spiking laser controlled by a delayed feedback

Author

Kovalev, Anton V., Viktorov, Evgeny, Erneux, Thomas, Kovalev, Anton V., Viktorov, Evgeny, and Erneux, Thomas

Abstract

In 1965, Statz et al. (J. Appl. Phys. 30, 1510 (1965)) investigated theoretically and experimentally the conditions under which spiking in the laser output can be completely suppressed by using a delayed optical feedback. In order to explore its effects, they formulate a delay differential equation model within the framework of laser rate equations. From their numerical simulations, they concluded that the feedback is effective in controlling the intensity laser pulses provided the delay is short enough. Ten years later, Krivoshchekov et al. (Sov. J. Quant. Electron. 5394 (1975)) reconsidered the Statz et al. delay differential equation and analyzed the limit of small delays. The stability conditions for arbitrary delays, however, were not determined. In this paper, we revisit Statz et al.’s delay differential equation model by using modern mathematical tools. We determine an asymptotic approximation of both the domains of stable steady states as well as a sub-domain of purely exponential transients., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2020

19. A highly coherent multi-section semiconductor swept source OCT laser

Author

Slepneva, Svetlana, primary, Kovalev, Anton V., additional, Roy, Aritra, additional, Patra, Sarojkanta, additional, Grigorenko, Konstantin, additional, Rebrova, Natalia, additional, Verschelde, Alexis, additional, Camelin, Patrice, additional, Roche, Amy, additional, Marconi, Mathias, additional, Giudici, Massimo, additional, Viktorov, Evgeny A., additional, Piwonski, Tomasz, additional, and Huyet, Guillaume, additional

Published
2020
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20. Distinct Laser Dynamics from a Single Figure-Eight Laser with an Integrated Nonlinear Waveguide

Author

Aadhi, A., primary, Roztocki, Piotr, additional, Kovalev, Anton V., additional, Kues, Michael, additional, Fischer, Bennet, additional, Reimer, Christian, additional, Zhang, Yanbing, additional, Wang, Tao, additional, Little, Brent E., additional, Chu, Sai T., additional, Wang, Zhiming, additional, Moss, David J., additional, Viktorov, Evgeny A., additional, and Morandotti, Roberto, additional

Published
2020
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21. Optical frequency comb generation by hybrid mode-locking in a nested cavity scheme

Author

Fischer, Bennet, primary, Rahim, Aadhi A., additional, Rimoldi, Cristina, additional, Roztocki, Piotr, additional, di Lauro, Luigi, additional, Chemnitz, Mario, additional, Kovalev, Anton V., additional, Chu, Sai T., additional, Little, Brent E., additional, Moss, David J., additional, Viktorov, Evgeny A., additional, Kues, Michael, additional, and Morandotti, Roberto, additional

Published
2020
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22. Dynamical regimes in a class A model of a nonlinear mirror mode-locked laser

Author

Vladimirov, Andrei G., Kovalev, Anton V., Viktorov, Evgeny A., Rebrova, Natalia, and Huyet, ##!Error: Attribute Unknown!

Subjects
delay differential equations, square waves, modulational instability, cavity solitons, Nonlinear mirror mode-locked lasers, 78M35, stability analysis, 42.65.Sf, 42.65.Re, 78A60, 42.60.Fc
Abstract

Using a simple delay differential equation model we study theoretically the dynamics of a unidirectional class-A ring laser with a nonlinear amplifying loop mirror. We perform analytical linear stability analysis of the CW regimes in the large delay limit and demonstrate that these regimes can be destabilized via modulational and Turing-type instabilities, as well as by a bifurcation leading to the appearance of square-waves. We investigate the formation of square-waves and mode-locked pulses in the system. We show that mode-locked pulses are very asymmetric with exponential decay of the trailing and superexponential growth of the leading edge. We discuss asymmetric interaction of these pulses leading to a formation of harmonic mode-locked regimes.

Published
2019
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23. Highly reconfigurable hybrid laser based on an integrated nonlinear waveguide

Author

Aadhi, A., Kovalev, Anton V., Kues, Michael, Roztocki, Piotr, Reimer, Christian, Zhang, Yanbing, Wang, Tao, Little, Brent E., Chu, Sai T., Wang, Zhiming, Moss, David J., Viktorov, Evgeny A., Morandotti, Roberto, Aadhi, A., Kovalev, Anton V., Kues, Michael, Roztocki, Piotr, Reimer, Christian, Zhang, Yanbing, Wang, Tao, Little, Brent E., Chu, Sai T., Wang, Zhiming, Moss, David J., Viktorov, Evgeny A., and Morandotti, Roberto

Abstract

The ability of laser systems to emit different adjustable temporal pulse profiles and patterns is desirable for a broad range of applications. While passive mode-locking techniques have been widely employed for the realization of ultrafast laser pulses with mainly Gaussian or hyperbolic secant temporal profiles, the generation of versatile pulse shapes in a controllable way and from a single laser system remains a challenge. Here we show that a nonlinear amplifying loop mirror (NALM) laser with a bandwidth-limiting filter (in a nearly dispersion-free arrangement) and a short integrated nonlinear waveguide enables the realization and distinct control of multiple mode-locked pulsing regimes (e.g., Gaussian pulses, square waves, fast sinusoidal-like oscillations) with repetition rates that are variable from the fundamental (7.63 MHz) through its 205th harmonic (1.56 GHz). These dynamics are described by a newly developed and compact theoretical model, which well agrees with our experimental results. It attributes the control of emission regimes to the change of the NALM response function that is achieved by the adjustable interplay between the NALM amplification and the nonlinearity. In contrast to previous square wave emissions, we experimentally observed that an Ikeda instability was responsible for square wave generation. The presented approach enables laser systems that can be universally applied to various applications, e.g., spectroscopy, ultrafast signal processing and generation of non-classical light states.

Published
2019

24. Highly reconfigurable hybrid laser based on an integrated nonlinear waveguide

Author

Aadhi, A., primary, Kovalev, Anton V., additional, Kues, Michael, additional, Roztocki, Piotr, additional, Reimer, Christian, additional, Zhang, Yanbing, additional, Wang, Tao, additional, Little, Brent E., additional, Chu, Sai T., additional, Wang, Zhiming, additional, Moss, David J., additional, Viktorov, Evgeny A., additional, and Morandotti, Roberto, additional

Published
2019
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32. Figure-eight Laser with an Integrated Nonlinear Waveguide: All-optical Square-wave Generation

Author

Kovalev, Anton V., primary, Aadhi, A., additional, Kues, Michael, additional, Roztocki, Piotr, additional, Reimer, Christian, additional, Zhang, Young, additional, Wang, Tao, additional, Matuhina, Anastasia, additional, Little, Brent E., additional, Chu, Sai T., additional, Moss, David J., additional, Wang, Zhiming, additional, Viktorov, Evgeny A., additional, and Morandotti, Roberto, additional

Published
2018
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35. Optical square waves from a nonlinear amplifying loop mirror laser (Conference Presentation)

Author

Aadhi, A., primary, Kovalev, Anton V., additional, Kues, Michael, additional, Roztocki, Piotr, additional, Reimer, Christian, additional, Zhang, Yanbing, additional, Wang, Tao, additional, Little, Brent E., additional, Chu, Sai T., additional, Moss, David J., additional, Wang, Zhiming, additional, Viktorov, Evgeny, additional, and Morandotti, Roberto, additional

Published
2018
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36. Dynamics of laser with an integrated nonlinear waveguide

Author

Aadhi, A., primary, Kovalev, Anton V., additional, Kues, Michael, additional, Roztocki, Piotr, additional, Reimer, Christian, additional, Zhang, Young, additional, Wang, Tao, additional, Little, Brent E., additional, Chu, Sai T., additional, Moss, David J., additional, Wang, Zhiming, additional, Viktorov, Evgeny A., additional, and Morandotti, Roberto, additional

Published
2018
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42. Pulse-burst Er:glass laser

Author

Vitkin, Vladimir V., additional, Dymshits, Olga S., additional, Polyakov, Vadim M., additional, Zhilin, Alexander A., additional, Shemchuk, Darya V., additional, Krylov, Alexandr A., additional, Uskov, Alexander V., additional, Mak, Andrey A., additional, and Kovalev, Anton V., additional

Published
2017
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43. Oviposition of the Fir Sawyer Beetle (Monochamus urussovi Fisch.) on the Tree Stem: Analysis Using Models of Random Point Fields

Author

Sekretenko, Olga P., Kovalev, Anton V., and Soukhovolsky, Vladislav G.

Subjects
случайное точечное поле, взаимодействие растений и насекомых, пространственная статистика, репродуктивная стратегия, spatial point process, point pattern, reproductive strategy, Monochamus urussovi Fisch, конкуренция за корм, food competition, plant-insect interaction, oviposition behaviour, spatial statistics
Abstract

Черный пихтовый усач – ксилофаг, образующий в темнохвойных лесах очаги массового размножения. Жуки при заселении дерева оставляют на стволе хорошо видимые насечки – отверстия, каждое из которых используется для помещения под кору одного яйца. Личинка в течение следующего лета питается лубом, образуя под корой непосредственно около насечки компактное повреждение. Для развития личинки необходима площадь питания не менее 50 см2. В настоящей работе проверено предположение о том, что самки размещают яйца так, чтобы уменьшить возможность перекрытия зон питания личинок. В очаге массового размножения по фотографиям поврежденных стволов были определены координаты 317 насечек. Методами пространственной статистики установлено, что размещение насечек является регуляризованным: в ближайшей окрестности каждой из них, как правило, количество других насечек значимо меньше, чем было бы при их независимом распределении. Размещение насечек описано моделью случайного точечного поля с негативным взаимодействием между его элементами. Показано, что интенсивность «расталкивающего взаимодействия» тем больше, чем меньше дистанция между насечками. Радиус взаимодействия составляет 4 см. Полученные результаты служат свидетельством в пользу того, что репродуктивная стратегия черного пихтового усача включает оптимизацию пространственного размещения потомства на стадии откладки яиц для уменьшения конкуренции за корм между будущими личинками. The fir sawyer beetle is a xylophagous species that develops outbreaks in boreal coniferous forests. Females deposit single eggs under the bark through slotted holes that they make by their mandibles. These oviposition scars are clearly visible while the tree is alive. Larvae feed on phloem and sapwood for one or two summers. Under the bark each larva forms compact damage area close to the oviposition scar. One larva needs an area of no less than 50 sq cm for feeding. In this study, we tested the hypothesis that adult females optimize the eggs’ spatial pattern to reduce the possibility that the feed zones of expectant larvae will overlap one another. This oviposition strategy reduces larvae competition and enhances their survival. During the outbreak’s peak phase the stems of damaged fir trees were photographed and the coordinates of the 317 oviposition scars were recorded. Spatial statistics was used to determine that the distribution of eggs on the stem surface is regularized: close to the oviposition scar the number of another scars are less than this number for the independent distribution of points. The point process model with negative interacion between points was fitted to the oviposition locations data. The force of the repulsive interaction was found diminishing with increasing of the distance between the scars. The radius of interaction was estimated to be 4 cm. Therefore, the reproductive strategy of the fir sawyer beetle includes oviposition behavior aimed to minimize larval competition

Published
2015

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