In any side-channel attack, it is desirable to exploit all the available leakage data to compute the distinguisher’s values. The profiling phase is essential to obtain an accurate leakage model, yet it may not be exh...In any side-channel attack, it is desirable to exploit all the available leakage data to compute the distinguisher’s values. The profiling phase is essential to obtain an accurate leakage model, yet it may not be exhaustive. As a result, information theoretic distinguishers may come up on previously unseen data, a phenomenon yielding empty bins. A strict application of the maximum likelihood method yields a distinguisher that is not even sound. Ignoring empty bins reestablishes soundness, but seriously limits its performance in terms of success rate. The purpose of this paper is to remedy this situation. In this research, we propose six different techniques to improve the performance of information theoretic distinguishers. We study t</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">hem thoroughly by applying them to timing attacks, both with synthetic and real leakages. Namely, we compare them in terms of success rate, and show that their performance depends on the amount of profiling, and can be explained by a bias-variance analysis. The result of our work is that there exist use-cases, especially when measurements are noisy, where our novel information theoretic distinguishers (typically the soft-drop distinguisher) perform the best compared to known side-channel distinguishers, despite the empty bin situation.展开更多
Stable laser emission with narrow linewidth is of critical importance in many applications,including coherent communications,LIDAR,and remote sensing.In this work,the physics underlying spectral narrowing of self-inje...Stable laser emission with narrow linewidth is of critical importance in many applications,including coherent communications,LIDAR,and remote sensing.In this work,the physics underlying spectral narrowing of self-injection-locked on-chip lasers to Hz-level lasing linewidth is investigated using a composite-cavity structure.Heterogeneously integrated III–V/SiN lasers operating with quantum-dot and quantum-well active regions are analyzed with a focus on the effects of carrier quantum confinement.The intrinsic differences are associated with gain saturation and carrier-induced refractive index,which are directly connected with 0-and 2-dimensional carrier densities of states.Results from parametric studies are presented for tradeoffs involved with tailoring the linewidth,output power,and injection current for different device configurations.Though both quantum-well and quantum-dot devices show similar linewidth-narrowing capabilities,the former emits at a higher optical power in the self-injection-locked state,while the latter is more energy-efficient.Lastly,a multi-objective optimization analysis is provided to optimize the operation and design parameters.For the quantum-well laser,minimizing the number of quantum-well layers is found to decrease the threshold current without significantly reducing the output power.For the quantum-dot laser,increasing the quantum-dot layers or density in each layer increases the output power without significantly increasing the threshold current.These findings serve to guide more detailed parametric studies to produce timely results for engineering design.展开更多
This work experimentally and theoretically demonstrates the effect of excited state lasing on the reflection sensitivity of dual-state quantum dot lasers,showing that the laser exhibits higher sensitivity to external ...This work experimentally and theoretically demonstrates the effect of excited state lasing on the reflection sensitivity of dual-state quantum dot lasers,showing that the laser exhibits higher sensitivity to external optical feedback when reaching the excited state lasing threshold.This sensitivity can be degraded by increasing the excited-to-ground-state energy separation,which results in a high excited-to-ground-state threshold ratio.In addition,the occurrence of excited state lasing decreases the damping factor and increases the linewidth enhancement factor,which leads to a low critical feedback level.These findings illuminate a path to fabricate reflectioninsensitive quantum dot lasers for isolator-free photonic integrated circuits.展开更多
A new notion of bent sequence related to Hadamard matrices was introduced recently,motivated by a security application(Solé,et al.,2021).The authors study the self-dual class in length at most 196.The authors use...A new notion of bent sequence related to Hadamard matrices was introduced recently,motivated by a security application(Solé,et al.,2021).The authors study the self-dual class in length at most 196.The authors use three competing methods of generation:Exhaustion,Linear Algebra and Gr?bner bases.Regular Hadamard matrices and Bush-type Hadamard matrices provide many examples.The authors conjecture that if v is an even perfect square,a self-dual bent sequence of length v always exists.The authors introduce the strong automorphism group of Hadamard matrices,which acts on their associated self-dual bent sequences.The authors give an efficient algorithm to compute that group.展开更多
Space-to-ground high-speed transmission is of utmost importance for the development of a worldwide broadband network.Mid-infrared wavelengths offer numerous advantages for building such a system,spanning from low atmo...Space-to-ground high-speed transmission is of utmost importance for the development of a worldwide broadband network.Mid-infrared wavelengths offer numerous advantages for building such a system,spanning from low atmospheric attenuation to eye-safe operation and resistance to inclement weather conditions.We demonstrate a full interband cascade system for high-speed transmission around a wavelength of 4.18μm.The low-power consumption of both the laser and the detector in combination with a large modulation bandwidth and sufficient output power makes this technology ideal for a free-space optical communication application.Our proof-of-concept experiment employs a radio-frequency optimized Fabry–Perot interband cascade laser and an interband cascade infrared photodetector based on a type-II InAs/GaSb superlattice.The bandwidth of the system is evaluated to be around 1.5 GHz.It allows us to achieve data rates of 12 Gbit/s with an on–off keying scheme and 14 Gbit/s with a 4-level pulse amplitude modulation scheme.The quality of the transmission is enhanced by conventional pre-and post-processing in order to be compatible with standard error-code correction.展开更多
This work investigates the dynamic and nonlinear properties of quantum dot(QD) lasers directly grown on silicon with a view to isolator-free applications. Among them, the chirp parameter, also named the αHfactor,is f...This work investigates the dynamic and nonlinear properties of quantum dot(QD) lasers directly grown on silicon with a view to isolator-free applications. Among them, the chirp parameter, also named the αHfactor,is featured through a thermally insensitive method analyzing the residual side-mode dynamics under optical injection locking. The αHat threshold is found as low as 0.32. Then, the nonlinear gain is investigated from the gain compression factor viewpoint. The latter is found higher for epitaxial QD lasers on silicon than that in heterogeneously integrated quantum well(QW) devices on silicon. Despite that, the power dependence of the αHdoes not lead to a large increase of the chirp coefficient above the laser’s threshold at higher bias. This effect is confirmed from an analytical model and attributed to the strong lasing emission of the ground-state transition, which transforms into a critical feedback level as high as-6.5 d B, which is ~19 d B higher than a comparable QW laser.Finally, the intensity noise analysis confirms that QD lasers are overdamped oscillators with damping frequencies as large as 33 GHz. Altogether, these features contribute to fundamentally enhancing the reflection insensitivity of the epitaxial QD lasers. This last feature is unveiled by the 10 Gbit/s error-free high-speed transmission experiments. Overall, we believe that this work is of paramount importance for future isolator-free photonics technologies and cost-efficient high-speed transmission systems.展开更多
Semiconductor nanostructures with low dimensionality like quantum dots and quantum dashes are one of the best attractive and heuristic solutions for achieving high performance photonic devices.When one or more spatial...Semiconductor nanostructures with low dimensionality like quantum dots and quantum dashes are one of the best attractive and heuristic solutions for achieving high performance photonic devices.When one or more spatial dimensions of the nanocrystal approach the de Broglie wavelength,nanoscale size effects create a spatial quantization of carriers leading to a complete discretization of energy levels along with additional quantum phenomena like entangled-photon generation or squeezed states of light among others.This article reviews our recent findings and prospects on nanostructure based light emitters where active region is made with quantum-dot and quantum-dash nanostructures.Many applications ranging from silicon-based integrated technologies to quantum information systems rely on the utilization of such laser sources.Here,we link the material and fundamental properties with the device physics.For this purpose,spectral linewidth,polarization anisotropy,optical nonlinearities as well as microwave,dynamic and nonlinear properties are closely examined.The paper focuses on photonic devices grown on native substrates(InP and GaAs)as well as those heterogeneously and epitaxially grown on silicon substrate.This research pipelines the most exciting recent innovation developed around light emitters using nanostructures as gain media and highlights the importance of nanotechnologies on industry and society especially for shaping the future information and communication society.展开更多
Chaos in nonlinear dynamical systems is featured with irregular appearance and with high sensitivity to initial conditions.Near-infrared light chaos based on semiconductor lasers has been extensively studied and has e...Chaos in nonlinear dynamical systems is featured with irregular appearance and with high sensitivity to initial conditions.Near-infrared light chaos based on semiconductor lasers has been extensively studied and has enabled various applications.Here,we report a fully-developed hyperchaos in the mid-infrared regime,which is produced from interband cascade lasers subject to the external optical feedback.Lyapunov spectrum analysis demonstrates that the chaos exhibits three positive Lyapunov exponents.Particularly,the chaotic signal covers a broad frequency range up to the GHz level,which is two to three orders of magnitude broader than existed mid-infrared chaos solutions.The interband cascade lasers produce either periodic oscillations or low-frequency fluctuations before bifurcating to hyperchaos.This hyperchaos source is valuable for developing long-reach secure optical communication links and remote chaotic Lidar systems,taking advantage of the high-transmission windows of the atmosphere in the mid-infrared regime.展开更多
The onset of nonlinear dynamics and chaos is evidenced in a mid-infrared distributed feedback quantum cascade laser both in the temporal and frequency domains.As opposed to the commonly observed route to chaos in semi...The onset of nonlinear dynamics and chaos is evidenced in a mid-infrared distributed feedback quantum cascade laser both in the temporal and frequency domains.As opposed to the commonly observed route to chaos in semiconductor lasers,which involves undamping of the laser relaxation oscillations,quantum cascade lasers first exhibit regular self-pulsation at the external cavity frequency before entering into a chaotic low-frequency fluctuation regime.The bifurcation sequence,similar to that already observed in class A gas lasers under optical feedback,results from the fast carrier relaxation dynamics occurring in quantum cascade lasers,as confirmed by numerical simulations.Such chaotic behavior can impact various practical applications including spectroscopy,which requires stable single-mode operation.It also allows the development of novel mid-infrared highpower chaotic light sources,thus enabling secure free-space high bit-rate optical communications based on chaos synchronization.展开更多
We demonstrate experimentally that mid-infrared quantum cascade lasers(QCLs)operating under external optical feedback exhibit extreme pulses.These events can be triggered by adding small amplitude periodic modulation,...We demonstrate experimentally that mid-infrared quantum cascade lasers(QCLs)operating under external optical feedback exhibit extreme pulses.These events can be triggered by adding small amplitude periodic modulation,with the highest success rate for the case of a pulse-up excitation.These findings broaden the potential applications for QCLs,which have already been proven to be a semiconductor laser of interest for spectroscopic applications and countermeasure systems.The ability to trigger extreme events paves the way for optical neuron-like systems where information propagates as a result of high intensity bursts.展开更多
This work reports on a high-efficiency In As/Ga As distributed feedback quantum dot laser.The large optical wavelength detuning at room temperature between the lasing peak and the gain peak causes the static,dynamic,a...This work reports on a high-efficiency In As/Ga As distributed feedback quantum dot laser.The large optical wavelength detuning at room temperature between the lasing peak and the gain peak causes the static,dynamic,and nonlinear intrinsic properties to all improve with temperature,including the lasing efficiency,the modulation dynamics,the linewidth enhancement factor,and consequently the reflection insensitivity.Results reported show an optimum operating temperature at 75°C,highlighting the potential of the large optical mismatch assisted single-frequency laser for the development of uncooled and isolator-free high-speed photonic integrated circuits.展开更多
We present a system for the removal of objects from videos. As input, the system only needs a user to draw a few strokes on the first frame, roughly delimiting the objects to be removed. To the best of our knowledge, ...We present a system for the removal of objects from videos. As input, the system only needs a user to draw a few strokes on the first frame, roughly delimiting the objects to be removed. To the best of our knowledge, this is the first system allowing the semi-automatic removal of objects from videos with complex backgrounds. The key steps of our system are the following: after initialization, segmentation masks are first refined and then automatically propagated through the video. Missing regions are then synthesized using video inpainting techniques. Our system can deal with multiple, possibly crossing objects, with complex motions, and with dynamic textures. This results in a computational tool that can alleviate tedious manual operations for editing high-quality videos.展开更多
The effects of gain compression on the modulation dynamics of an optically injected gain lever semiconductor laser are studied. Calculations reveal that the gain compression is not necessarily a drawback affecting the...The effects of gain compression on the modulation dynamics of an optically injected gain lever semiconductor laser are studied. Calculations reveal that the gain compression is not necessarily a drawback affecting the laser dynamics. With a practical injection strength, a high gain lever effect and a moderate compression value allow us to theoretically predict a modulation bandwidth four times higher than the free-running one without a gain lever,which is of paramount importance for the development of directly modulated broadband optical sources compatible with short-reach communication links.展开更多
Free-space optical communication is a very promising alternative to fiber communication systems,in terms of ease of deployment and costs.Midinfrared light has several features of utter relevance for free-space applica...Free-space optical communication is a very promising alternative to fiber communication systems,in terms of ease of deployment and costs.Midinfrared light has several features of utter relevance for free-space applications:low absorption when propagating in the atmosphere even under adverse conditions,robustness of the wavefront during long-distance propagation,and absence of regulations and restrictions for this range of wavelengths.A proof-of-concept of high-speed transmission taking advantage of intersubband devices has recently been demonstrated,but this effort was limited by the short-distance optical path(up to 1 m).In this work,we study the possibility of building a long-range link using unipolar quantum optoelectronics.Two different detectors are used:an uncooled quantum cascade detector and a nitrogen-cooled quantum well-infrared photodetector.We evaluate the maximum data rate of our link in a back-to-back configuration before adding a Herriott cell to increase the length of the light path up to 31 m.By using pulse shaping,pre-and post-processing,we reach a record bitrate of 30 Gbit s−1 for both two-level(OOK)and four-level(PAM-4)modulation schemes for a 31-m propagation link and a bit error rate compatible with error-correction codes.展开更多
This work compares the four-wave mixing(FWM)effect in epitaxial quantum dot(QD)lasers grown on silicon with quantum well(QW)lasers.A comparison of theory and experiment results shows that the measured FWM coefficient ...This work compares the four-wave mixing(FWM)effect in epitaxial quantum dot(QD)lasers grown on silicon with quantum well(QW)lasers.A comparison of theory and experiment results shows that the measured FWM coefficient is in good agreement with theoretical predictions.The gain in signal power is higher for p-doped QD lasers than for undoped lasers,despite the same FWM coefficient.Owing to the near-zero linewidth enhancement factor,QD lasers exhibit FWM coefficients and conversion efficiency that are more than one order of magnitude higher than those of QW lasers.Thus,this leads to self-mode locking in QD lasers.These findings are useful for developing on-chip sources for photonic integrated circuits on silicon.展开更多
文摘In any side-channel attack, it is desirable to exploit all the available leakage data to compute the distinguisher’s values. The profiling phase is essential to obtain an accurate leakage model, yet it may not be exhaustive. As a result, information theoretic distinguishers may come up on previously unseen data, a phenomenon yielding empty bins. A strict application of the maximum likelihood method yields a distinguisher that is not even sound. Ignoring empty bins reestablishes soundness, but seriously limits its performance in terms of success rate. The purpose of this paper is to remedy this situation. In this research, we propose six different techniques to improve the performance of information theoretic distinguishers. We study t</span></span><span style="font-family:Verdana;"><span style="font-family:Verdana;"><span style="font-family:Verdana;">hem thoroughly by applying them to timing attacks, both with synthetic and real leakages. Namely, we compare them in terms of success rate, and show that their performance depends on the amount of profiling, and can be explained by a bias-variance analysis. The result of our work is that there exist use-cases, especially when measurements are noisy, where our novel information theoretic distinguishers (typically the soft-drop distinguisher) perform the best compared to known side-channel distinguishers, despite the empty bin situation.
基金supported by King Abdullah University of Science and Technology(KAUST)Research Funding(KRF)under Award No.ORA-2022-5314Advanced Research Projects Agency-Energy(ARPA-E)No.DE-AR000067+1 种基金the U.S.Department of Energy under Contract No.DE-AC04-94AL85000the American Institute for Manufacturing(AIM)Integrated Photonics.
文摘Stable laser emission with narrow linewidth is of critical importance in many applications,including coherent communications,LIDAR,and remote sensing.In this work,the physics underlying spectral narrowing of self-injection-locked on-chip lasers to Hz-level lasing linewidth is investigated using a composite-cavity structure.Heterogeneously integrated III–V/SiN lasers operating with quantum-dot and quantum-well active regions are analyzed with a focus on the effects of carrier quantum confinement.The intrinsic differences are associated with gain saturation and carrier-induced refractive index,which are directly connected with 0-and 2-dimensional carrier densities of states.Results from parametric studies are presented for tradeoffs involved with tailoring the linewidth,output power,and injection current for different device configurations.Though both quantum-well and quantum-dot devices show similar linewidth-narrowing capabilities,the former emits at a higher optical power in the self-injection-locked state,while the latter is more energy-efficient.Lastly,a multi-objective optimization analysis is provided to optimize the operation and design parameters.For the quantum-well laser,minimizing the number of quantum-well layers is found to decrease the threshold current without significantly reducing the output power.For the quantum-dot laser,increasing the quantum-dot layers or density in each layer increases the output power without significantly increasing the threshold current.These findings serve to guide more detailed parametric studies to produce timely results for engineering design.
基金National Key Research and Development Program of China(2022YFB2803600)National Natural Science Foundation of China(62204072,U22A2093)+1 种基金Basic and Applied Basic Research Foundation of Guangdong Province(2021A1515110076,2023A1515012304)Shenzhen Science and Technology Innovation Program(GXWD20220811163623002,RCBS20210609103824050)。
文摘This work experimentally and theoretically demonstrates the effect of excited state lasing on the reflection sensitivity of dual-state quantum dot lasers,showing that the laser exhibits higher sensitivity to external optical feedback when reaching the excited state lasing threshold.This sensitivity can be degraded by increasing the excited-to-ground-state energy separation,which results in a high excited-to-ground-state threshold ratio.In addition,the occurrence of excited state lasing decreases the damping factor and increases the linewidth enhancement factor,which leads to a low critical feedback level.These findings illuminate a path to fabricate reflectioninsensitive quantum dot lasers for isolator-free photonic integrated circuits.
基金supported in part by the National Natural Science Foundation of China under Grant No.12071001The work of Dean Crnkovi?is supported by Croatian Science Foundation under the project 6732。
文摘A new notion of bent sequence related to Hadamard matrices was introduced recently,motivated by a security application(Solé,et al.,2021).The authors study the self-dual class in length at most 196.The authors use three competing methods of generation:Exhaustion,Linear Algebra and Gr?bner bases.Regular Hadamard matrices and Bush-type Hadamard matrices provide many examples.The authors conjecture that if v is an even perfect square,a self-dual bent sequence of length v always exists.The authors introduce the strong automorphism group of Hadamard matrices,which acts on their associated self-dual bent sequences.The authors give an efficient algorithm to compute that group.
基金Agence Nationale de la Recherche(ANR-11-EQPX-0016,ANR-17-ASMA0006)Direction Générale de l’Armement(DGA)+1 种基金European Office of Aerospace Research and Development(FA9550-18-1-7001)European Research Council(853014)。
文摘Space-to-ground high-speed transmission is of utmost importance for the development of a worldwide broadband network.Mid-infrared wavelengths offer numerous advantages for building such a system,spanning from low atmospheric attenuation to eye-safe operation and resistance to inclement weather conditions.We demonstrate a full interband cascade system for high-speed transmission around a wavelength of 4.18μm.The low-power consumption of both the laser and the detector in combination with a large modulation bandwidth and sufficient output power makes this technology ideal for a free-space optical communication application.Our proof-of-concept experiment employs a radio-frequency optimized Fabry–Perot interband cascade laser and an interband cascade infrared photodetector based on a type-II InAs/GaSb superlattice.The bandwidth of the system is evaluated to be around 1.5 GHz.It allows us to achieve data rates of 12 Gbit/s with an on–off keying scheme and 14 Gbit/s with a 4-level pulse amplitude modulation scheme.The quality of the transmission is enhanced by conventional pre-and post-processing in order to be compatible with standard error-code correction.
基金ENLITENED programAdvanced Research Projects Agency—Energy(DE-AR0000843)+1 种基金Institut MinesTélécomChina Scholarship Council
文摘This work investigates the dynamic and nonlinear properties of quantum dot(QD) lasers directly grown on silicon with a view to isolator-free applications. Among them, the chirp parameter, also named the αHfactor,is featured through a thermally insensitive method analyzing the residual side-mode dynamics under optical injection locking. The αHat threshold is found as low as 0.32. Then, the nonlinear gain is investigated from the gain compression factor viewpoint. The latter is found higher for epitaxial QD lasers on silicon than that in heterogeneously integrated quantum well(QW) devices on silicon. Despite that, the power dependence of the αHdoes not lead to a large increase of the chirp coefficient above the laser’s threshold at higher bias. This effect is confirmed from an analytical model and attributed to the strong lasing emission of the ground-state transition, which transforms into a critical feedback level as high as-6.5 d B, which is ~19 d B higher than a comparable QW laser.Finally, the intensity noise analysis confirms that QD lasers are overdamped oscillators with damping frequencies as large as 33 GHz. Altogether, these features contribute to fundamentally enhancing the reflection insensitivity of the epitaxial QD lasers. This last feature is unveiled by the 10 Gbit/s error-free high-speed transmission experiments. Overall, we believe that this work is of paramount importance for future isolator-free photonics technologies and cost-efficient high-speed transmission systems.
文摘Semiconductor nanostructures with low dimensionality like quantum dots and quantum dashes are one of the best attractive and heuristic solutions for achieving high performance photonic devices.When one or more spatial dimensions of the nanocrystal approach the de Broglie wavelength,nanoscale size effects create a spatial quantization of carriers leading to a complete discretization of energy levels along with additional quantum phenomena like entangled-photon generation or squeezed states of light among others.This article reviews our recent findings and prospects on nanostructure based light emitters where active region is made with quantum-dot and quantum-dash nanostructures.Many applications ranging from silicon-based integrated technologies to quantum information systems rely on the utilization of such laser sources.Here,we link the material and fundamental properties with the device physics.For this purpose,spectral linewidth,polarization anisotropy,optical nonlinearities as well as microwave,dynamic and nonlinear properties are closely examined.The paper focuses on photonic devices grown on native substrates(InP and GaAs)as well as those heterogeneously and epitaxially grown on silicon substrate.This research pipelines the most exciting recent innovation developed around light emitters using nanostructures as gain media and highlights the importance of nanotechnologies on industry and society especially for shaping the future information and communication society.
基金Shanghai Natural Science Foundation(20ZR1436500)National Natural Science Foundation of China(61804095,61875168).
文摘Chaos in nonlinear dynamical systems is featured with irregular appearance and with high sensitivity to initial conditions.Near-infrared light chaos based on semiconductor lasers has been extensively studied and has enabled various applications.Here,we report a fully-developed hyperchaos in the mid-infrared regime,which is produced from interband cascade lasers subject to the external optical feedback.Lyapunov spectrum analysis demonstrates that the chaos exhibits three positive Lyapunov exponents.Particularly,the chaotic signal covers a broad frequency range up to the GHz level,which is two to three orders of magnitude broader than existed mid-infrared chaos solutions.The interband cascade lasers produce either periodic oscillations or low-frequency fluctuations before bifurcating to hyperchaos.This hyperchaos source is valuable for developing long-reach secure optical communication links and remote chaotic Lidar systems,taking advantage of the high-transmission windows of the atmosphere in the mid-infrared regime.
基金funded by the Direction Générale de l'Armement(DGA)the support of the French National research Agency(ANR)through the Nanodesign Project funded by the IDEX Paris-Saclay,ANR-11-IDEX-0003-02+2 种基金support of Préfecture de Lorraine and SGAR for the projects PHOTON(FEDER)and APOLLO(FEDER and FNADT)the support of Conseil Régional de Lorraine,Fondation Supélec,ANR through the TINO project(ANR-12-JS03-005)the Inter-University Attraction Pole Program IAP VII P7/35‘Photonics@be’.
文摘The onset of nonlinear dynamics and chaos is evidenced in a mid-infrared distributed feedback quantum cascade laser both in the temporal and frequency domains.As opposed to the commonly observed route to chaos in semiconductor lasers,which involves undamping of the laser relaxation oscillations,quantum cascade lasers first exhibit regular self-pulsation at the external cavity frequency before entering into a chaotic low-frequency fluctuation regime.The bifurcation sequence,similar to that already observed in class A gas lasers under optical feedback,results from the fast carrier relaxation dynamics occurring in quantum cascade lasers,as confirmed by numerical simulations.Such chaotic behavior can impact various practical applications including spectroscopy,which requires stable single-mode operation.It also allows the development of novel mid-infrared highpower chaotic light sources,thus enabling secure free-space high bit-rate optical communications based on chaos synchronization.
基金Thiswork was supported by the French Defense Agency (DGA), theFrench ANR program (ANR-17-ASMA-0006)the EuropeanOffice of Aerospace Research and Development (FA9550-18-1-7001)+1 种基金the Office of Naval Research (N00014-16-1-2094)the National Science Foundation (DMR-1611598).
文摘We demonstrate experimentally that mid-infrared quantum cascade lasers(QCLs)operating under external optical feedback exhibit extreme pulses.These events can be triggered by adding small amplitude periodic modulation,with the highest success rate for the case of a pulse-up excitation.These findings broaden the potential applications for QCLs,which have already been proven to be a semiconductor laser of interest for spectroscopic applications and countermeasure systems.The ability to trigger extreme events paves the way for optical neuron-like systems where information propagates as a result of high intensity bursts.
基金Advanced Research Projects Agency—Energy(DE-AR0001039)。
文摘This work reports on a high-efficiency In As/Ga As distributed feedback quantum dot laser.The large optical wavelength detuning at room temperature between the lasing peak and the gain peak causes the static,dynamic,and nonlinear intrinsic properties to all improve with temperature,including the lasing efficiency,the modulation dynamics,the linewidth enhancement factor,and consequently the reflection insensitivity.Results reported show an optimum operating temperature at 75°C,highlighting the potential of the large optical mismatch assisted single-frequency laser for the development of uncooled and isolator-free high-speed photonic integrated circuits.
基金funded by the French Research Agency (ANR) under Grant No. ANR-14-CE27-001 (MIRIAM)
文摘We present a system for the removal of objects from videos. As input, the system only needs a user to draw a few strokes on the first frame, roughly delimiting the objects to be removed. To the best of our knowledge, this is the first system allowing the semi-automatic removal of objects from videos with complex backgrounds. The key steps of our system are the following: after initialization, segmentation masks are first refined and then automatically propagated through the video. Missing regions are then synthesized using video inpainting techniques. Our system can deal with multiple, possibly crossing objects, with complex motions, and with dynamic textures. This results in a computational tool that can alleviate tedious manual operations for editing high-quality videos.
基金European Office of Aerospace Research and Development(FA9550-15-1-0104)
文摘The effects of gain compression on the modulation dynamics of an optically injected gain lever semiconductor laser are studied. Calculations reveal that the gain compression is not necessarily a drawback affecting the laser dynamics. With a practical injection strength, a high gain lever effect and a moderate compression value allow us to theoretically predict a modulation bandwidth four times higher than the free-running one without a gain lever,which is of paramount importance for the development of directly modulated broadband optical sources compatible with short-reach communication links.
基金the financial support of the Direction Générale de l’Armement(DGA)the ENS-Thales Chair,ANR project LIGNEDEMIR(ANR-18CE09-0035)+1 种基金FETOpen 2018–2020 Horizon 2020 projects cFLOW(Grant No.828893)QOMBS(Grant No.820419)and CNRS Renatech network.
文摘Free-space optical communication is a very promising alternative to fiber communication systems,in terms of ease of deployment and costs.Midinfrared light has several features of utter relevance for free-space applications:low absorption when propagating in the atmosphere even under adverse conditions,robustness of the wavefront during long-distance propagation,and absence of regulations and restrictions for this range of wavelengths.A proof-of-concept of high-speed transmission taking advantage of intersubband devices has recently been demonstrated,but this effort was limited by the short-distance optical path(up to 1 m).In this work,we study the possibility of building a long-range link using unipolar quantum optoelectronics.Two different detectors are used:an uncooled quantum cascade detector and a nitrogen-cooled quantum well-infrared photodetector.We evaluate the maximum data rate of our link in a back-to-back configuration before adding a Herriott cell to increase the length of the light path up to 31 m.By using pulse shaping,pre-and post-processing,we reach a record bitrate of 30 Gbit s−1 for both two-level(OOK)and four-level(PAM-4)modulation schemes for a 31-m propagation link and a bit error rate compatible with error-correction codes.
基金Basic and Applied Basic Research Foundation of Guangdong Province(2021A1515110076)Center for Integrated Nanotechnologies,an Office of Science User Facility operated for the U.S.Department of Energy(DOE)Office of Science by Los Alamos National Laboratory(2021BC0057)DARPA PIPES(HR0011-19-C-0083).
文摘This work compares the four-wave mixing(FWM)effect in epitaxial quantum dot(QD)lasers grown on silicon with quantum well(QW)lasers.A comparison of theory and experiment results shows that the measured FWM coefficient is in good agreement with theoretical predictions.The gain in signal power is higher for p-doped QD lasers than for undoped lasers,despite the same FWM coefficient.Owing to the near-zero linewidth enhancement factor,QD lasers exhibit FWM coefficients and conversion efficiency that are more than one order of magnitude higher than those of QW lasers.Thus,this leads to self-mode locking in QD lasers.These findings are useful for developing on-chip sources for photonic integrated circuits on silicon.