- 标题
- 摘要
- 关键词
- 实验方案
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[IEEE 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Huangshan, China (2019.8.5-2019.8.8)] 2019 18th International Conference on Optical Communications and Networks (ICOCN) - Deterministic Single Soliton Generation Driven by Chirped Optical Pulses in Kerr Microresonator
摘要： Deterministic single soliton corresponding to a smooth Kerr combs is more favored in applications. However, precise and rapid control, stochastic solitons number and low conversion efficiency are great challenges in the microresonator (MRR) driven by continuous-wave (c.w.). In this paper, we show that the MRR driving by chirped optical pulse can effectively overcome these issues. Deterministic single soliton can be produced when the chirp parameter is larger than the threshold with proper final pump phase detuning. Once above the threshold, the chirp parameter and pulse duration have no significant effects on the soliton peak power and bandwidth indicating a flexible choice o f driving pulse. Nevertheless, the soliton peak power and bandwidth can be simply controlled by the final detuning.
关键词： chirped optical pulses,Kerr combs,microresonator,Deterministic Single soliton generation
更新于2025-09-16 10:30:52
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Nonlinear Fiber Optics || Group-velocity dispersion
摘要： The preceding chapter showed how the combined effects of group-velocity dispersion (GVD) and self-phase modulation (SPM) on optical pulses propagating inside a fiber can be studied by solving a pulse-propagation equation. Before considering the general case, it is instructive to study the effects of GVD alone. This chapter considers the pulse-propagation problem by treating fibers as a linear optical medium. In Section 3.1 we discuss the conditions under which the GVD effects dominate over the nonlinear effects by introducing two length scales associated with GVD and SPM. Dispersion-induced broadening of optical pulses is considered in Section 3.2 for several specific pulse shapes, including Gaussian and 'sech' pulses. The effects of initial frequency chirping are also discussed in this section. Section 3.3 is devoted to the effects of third-order dispersion on pulse broadening. An analytic theory capable of predicting dispersive broadening for pulses of arbitrary shapes is also given in this section. We discuss in Section 3.4 how the GVD can limit the performance of optical communication systems and how the technique of dispersion management can be used to combat such limitations.
关键词： dispersion management,dispersion-induced broadening,sech pulses,Group-velocity dispersion,GVD,optical pulses,third-order dispersion,SPM,Gaussian pulses,self-phase modulation,fiber propagation,frequency chirping
更新于2025-09-12 10:27:22
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Nonlinear Fiber Optics || Self-phase modulation
摘要： The ?rst nonlinear effect that we focus on is the self-phase modulation (SPM), a phenomenon that leads to spectral broadening of optical pulses [1–9]. SPM is the temporal analog of self-focusing of CW beams occurring inside any nonlinear medium with n2 > 0. It was ?rst observed in 1967 in the context of transient self-focusing of optical pulses propagating through a CS2-?lled cell [1]. By 1970, SPM had been observed in solids and glasses by using picosecond pulses. The earliest observation of SPM in optical ?bers was made with a ?ber whose core was ?lled with CS2 liquid [7]. This work led by 1978 to a systematic study of SPM in a silica-core ?ber [9]. This chapter considers SPM as a simple example of the nonlinear effects that can occur inside optical ?bers. Section 4.1 is devoted to the case of pure SPM as it neglects the GVD effects and focuses on spectral changes induced by SPM. The combined effects of GVD and SPM are discussed in Section 4.2 with emphasis on the SPM-induced frequency chirp. Section 4.3 presents two analytic techniques and uses them to solve the NLS equation approximately. Section 4.4 extends the analysis to include the higher-order nonlinear effects such as self-steepening.
关键词： GVD,self-steepening,spectral broadening,optical pulses,frequency chirp,SPM,nonlinear effects,NLS equation,self-phase modulation
更新于2025-09-12 10:27:22
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Customizing Supercontinuum Generation Via Adaptive On-Chip Pulse Splitting
摘要： Modern optical systems increasingly rely on complex physical processes. Advanced light sources, such as supercontinuum (SC) [1], are highly sought for imaging and metrology, and are based on nonlinear dynamics where the output properties must often finely match target performance characteristics. However, in these systems, the availability of control parameters and the means to adjust them in a versatile manner are usually limited. Moreover, finding the ideal parameters for a specific application can become inherently complex. Here, we use an actively-controlled photonic chip to prepare and manipulate patterns of femtosecond optical pulses seeding supercontinuum generation [1]. Taking advantage of machine learning concepts [2], we exploit this access to an enhanced and tunable parameter space and experimentally demonstrate the customization of nonlinear interactions responsible for tailoring supercontinuum properties [3].
关键词： femtosecond optical pulses,supercontinuum generation,photonic chip,machine learning,nonlinear dynamics
更新于2025-09-12 10:27:22
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Generalized Method to Describe the Propagation of Pulses in Classical and Specialty Optical Fibers
摘要： The comprehension of pulsed light propagation is of paramount importance in fiber optics. Here, we present a general method to describe the propagation of pulses in any kind of optical fiber, regardless of its fabrication process or constituent materials. As a result, we obtain a rich toolbox for the analysis and synthesis of optical fibers, which allows us to circumvent the resolution of Maxwell’s equations by using heavy-computational numerical methods. To illustrate this, we analyze the pulse propagation problem in non-paraxial anisotropic single-core and multi-core fibers that cover a large variety of optical fibers including classical weakly guiding fibers, optical gain fibers, polarization-maintaining fibers, highly nonlinear fibers, and photonic crystal fibers. Moreover, it is shown that our method can be applied to any kind of guided and unguided medium undergoing spatial and temporal perturbations, provided that the distance and temporal width between different consecutive spatial and temporal medium perturbations are respectively higher than the spatial and temporal width of the optical pulses.
关键词： Optical fiber,nonlinear optics,optical pulses
更新于2025-09-11 14:15:04
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[IEEE 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Munich, Germany (2019.6.23-2019.6.27)] 2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference (CLEO/Europe-EQEC) - Soliton Self-Compression in Hollow Capillary Fibres
摘要： The creation of shorter and shorter optical pulses at higher and higher energies has been one of the primary aims of laser science and nonlinear optics. At high energies (few mJ), the dominant technique is currently the use of self-phase modulation (SPM) and self-steepening in a gas-filled hollow capillary fibre (HCF) to spectrally broaden pump pulses (typically ~30 fs), followed by chirped mirrors to compensate the phase variation across the spectrum and hence achieve pulse compression [1]. In this way high-energy single-cycle pulses are routinely generated. An alternative route to shorter pulses is soliton self-compression, where the dispersion of the fibre is tuned to be anomalous such that it continuously compensates the phase of the pulse as its spectrum expands. This technique is widely established at low power in solid-core optical fibres and at few-μJ energies in hollow-core photonic-crystal fibres (HC-PCF) [2]. Here we experimentally demonstrate soliton self-compression in conventional gas-filled HCF at much higher energy [3]. We will describe how our technique opens the door to generating 1 fs, 1 TW optical pulses.
关键词： optical pulses,nonlinear optics,hollow capillary fibres,soliton self-compression
更新于2025-09-11 14:15:04
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Particle-in-cell simulation of ultrafast hot-carrier transport in Fe/Au heterostructures
摘要： We present a theoretical approach for spin-polarized hot-electron transport, as it occurs after excitation by ultrafast optical pulses in heterostructures formed by ferromagnetic and normal metals. We formulate a spin-dependent particle-in-cell model that solves the Boltzmann equation for excited electrons. It includes lifetimes and transmission coefficients as parameters, which can be taken from ab initio calculations or experiment, and can be easily extended to multilayer systems. This approach is capable of describing electron transport in the ballistic, superdiffusive, and diffusive regime including secondary-carrier generation. We apply the model to optically excited carriers in Fe/Au bilayers and Fe/Au/Fe spin-valve structures and analyze theoretically the hot-electron transport dynamics probed in recent experiments on spin valves. We find contributions to the demagnetization dynamics induced in Fe/Au/Fe trilayers regardless of the parallel or antiparallel magnetic alignment of the Fe layers.
关键词： ferromagnetic and normal metals,ultrafast optical pulses,Fe/Au/Fe spin-valve structures,Fe/Au bilayers,Boltzmann equation,spin-polarized hot-electron transport
更新于2025-09-04 15:30:14