- 标题
- 摘要
- 关键词
- 实验方案
- 产品
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A perturbative approach to self-phase modulation and self-steepening of short laser pulses propagating in nonlinear media
摘要： The solution of the wave equation in the envelope approximation with temporal corrections for a laser pulse propagating in a medium where the Kerr effect, field ionization, and associated absorption take place, is obtained through a first order perturbative approach. Dispersion is, however, neglected to decouple the equations for the amplitude and the phase. The closed-form expressions so obtained clarify the influence of the various terms of the equation on the laser amplitude and on the frequency generation as a function of the retarded time. Furthermore, they allow extracting scaling parameters which size the nonlinear effects. The results are illustrated quantitatively in the case of a femtosecond pulse focused in the air with typical parameters.
关键词： perturbative approach,self-phase modulation,self-steepening,short laser pulse propagation
更新于2025-09-23 15:21:01
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Raman scattering and self-steepening in nonlinear plasmonic waveguide pulse equation
摘要： In this paper, we use Maxwell equations and the first order perturbation theory to obtain pulse propagation equation in a plasmonic waveguide made of nonlinear dielectric material. In this study, the effects of nonlinear self-steepening and Raman scattering are considered. Nonlinear coefficients of phase modulation, Raman and self-steepening are calculated numerically in terms of frequency and compared with a standard silica fiber. Obtained values of the nonlinear coefficients are about up to 300 times larger than that of standard silica optical fibers. So they can be used as part of all optical integrated circuit such as continuum generation, optical switching and frequency conversion.
关键词： Nonlinear optics,Self-steepening,Raman scattering,Nonlinear plasmonic waveguide
更新于2025-09-19 17:13:59
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Extenuation of phase shift influenced nonlinear impairments in fiber optics network
摘要： Transmission of ultrahigh data rates through fiber optics networks (FONs) over long transmission distances in an intensity-dependent refractive index medium suffers from nonlinear self-steepening (NSS) and stimulated Raman scattering (SRS). In this paper, a FON model is proposed to compensate NSS and SRS impairments, using a theoretical model and its verification through simulation for different set of parameters. The proposed FON is designed to support 8, 16, and 32 channels with dual polarization quadrature phase shift keying modulation format. The analysis is performed for a range of values for the transmission medium including nonlinear effective area, nonlinear refractive index, and nonlinear dispersion. Moreover, the performance of the proposed model is evaluated in terms of launch power, polarization variations, received power, and length of transmission fiber. The overall work is analyzed for transmission distances up to 1200 km for performance metric of bit error rate, eye diagram, and received symbols constellations diagram.
关键词： WDM,stimulated Raman scattering,quadrature phase shift keying,fiber optics networks,nonlinear self-steepening,phase shift
更新于2025-09-16 10:30:52
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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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Nonlinear Fiber Optics || Optical solitons
摘要： A fascinating manifestation of the fiber nonlinearity occurs through optical solitons, formed as a result of the interplay between the dispersive and nonlinear effects. The word soliton refers to special kinds of wave packets that can propagate undistorted over long distances. Solitons have been discovered in many branches of physics. This chapter focuses on pulse propagation inside optical fibers in the regime in which both the group-velocity dispersion (GVD) and self-phase modulation (SPM) are equally important and must be considered simultaneously. It is organized as follows. Section 5.1 considers the phenomenon of modulation instability and shows that propagation of a continuous-wave (CW) beam inside optical fibers is inherently unstable and may convert the CW beam into pulse train under appropriate conditions. The inverse-scattering method is discussed in Section 5.2 together with the soliton solutions. The properties of the fundamental and higher-order solitons are also discussed in this section. Section 5.3 is devoted to other kinds of solitons, with emphasis on dark solitons. Section 5.4 considers the effects of external perturbations on solitons. Perturbations discussed include fiber losses, amplification of solitons, and noise introduced by optical amplifiers. Higher-order nonlinear effects such as self-steepening and intrapulse Raman scattering are the focus of Sections 5.5 and 5.6.
关键词： modulation instability,optical amplifiers,dark solitons,intrapulse Raman scattering,inverse-scattering method,self-steepening,group-velocity dispersion,fiber nonlinearity,self-phase modulation,fiber losses,optical solitons
更新于2025-09-12 10:27:22
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Low-threshold 4/5 octave-spanning mid-infrared frequency comb in a LiNbO3 microresonator
摘要： Mid-infrared (MIR) optical frequency combs (OFCs) are ideal light sources for precision metrology and can ?nd extensive applications, especially in molecular spectroscopy and gas detection. Here the generation of mode-locked MIR frequency comb in a LiNbO3 microring through optimized slot-waveguide design is proposed. Such microcomb can span over four-?fths of an octave (ranging from (cid:24)2810 nm to (cid:24)4630 nm) with pump power as low as 50 mW, which can be applied to the 2f -3f self-referencing for fully stabilization and helpful to monolithic integration of the whole system. Further investigations on complex dynamical processes for the microcomb generation suggest that the intracavity soliton drifting caused by the third-order dispersion could be compensated by the self-steepening effect as introducing an additional drift through proper dispersion tailoring. This work could facilitate the low-threshold broadband MIR frequency comb generation technique, as well as provide a way to realize more delicate control of soliton microcombs in both temporal and spectral domain.
关键词： mid-infrared,high-order dispersion,self-steepening,Lithium niobate,nonlinear optics
更新于2025-09-11 14:15:04
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Study of Optical Soliton Perturbation with Quadratic-Cubic Nonlinearity by Lie Symmetry and Group Invariance
摘要： Here, optical soliton perturbation with quadratic-cubic nonlinearity has been discussed by applying Lie symmetry and group invariants. The perturbation terms include third and fourth order dispersions in addition to self-steepening, intermodal dispersion and higher order dispersion effects. Using presented algorithms, Bright and dark soliton solutions are revealed.
关键词： group invariants,higher order dispersion effects,third and fourth order dispersions,optical soliton perturbation,Lie symmetry,quadratic-cubic nonlinearity,Bright and dark soliton solutions,self-steepening,intermodal dispersion
更新于2025-09-04 15:30:14