作者机构：
[Deng, Zhixiang; Fan, Dianyuan; Chen, Yu; Liu, Jun] Shenzhen Univ, Minist Educ & Guangdong Prov, Key Lab Optoelect Devices & Syst,Coll Optoelect E, Int Collaborat Lab 2D Mat Optoelect Sci & Technol, Shenzhen 518060, Peoples R China.;[Deng, Zhixiang] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Zhao, Chujun] Hunan Univ, Sch Phys & Elect, IFSA Collaborat Innovat Ctr, Minist Educ,Lab Micronanooptoelect Devices, Changsha 410082, Peoples R China.
通讯机构：
[Liu, Jun] S;Shenzhen Univ, Minist Educ & Guangdong Prov, Key Lab Optoelect Devices & Syst,Coll Optoelect E, Int Collaborat Lab 2D Mat Optoelect Sci & Technol, Shenzhen 518060, Peoples R China.
摘要：
The spectral analysis of the light propagating in normally dispersive graded-index multimode fibers is performed under initial noisy conditions. Based on the obtained spectra with multiple simulations in the presence of noise, we investigate the correlation in energy between the well-separated spectral sidebands through both the scattergrams and the frequency-dependent energy correlation map and find that conjugate couples are highly correlated while cross-combinations exhibit a very poor degree of correlation. These results reveal that the geometric parametric instability processes associated with each sideband pair occur independently from each other, which can provide significant insights into the fundamental dynamical effect of the geometric parametric instability and facilitate the future implementation of high-efficiency photon pair sources with reduced Raman decorrelations.
作者机构：
[Deng, Zhixiang; Fan, Dianyuan; Chen, Yu; Liu, Jun] Shenzhen Univ, Int Collaborat Lab 2D Mat Optoelect Sci & Technol, Key Lab Optoelect Devices & Syst, Minist Educ & Guangdong Prov,Coll Optoelect Engn, Shenzhen 518060, Peoples R China.;[Deng, Zhixiang] Univ South China, Sch Elect Engn, Hengyang 421001, Peoples R China.;[Liu, Jun] Aston Univ, Sch Engn & Appl Sci, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England.;[Zhao, Chujun] Hunan Univ, Sch Phys & Elect, IFSA Collaborat Innovat Ctr, Lab Micro Nanooptoelect Devices,Minist Educ, Changsha 410082, Hunan, Peoples R China.
通讯机构：
[Liu, Jun] S;[Liu, Jun] A;Shenzhen Univ, Int Collaborat Lab 2D Mat Optoelect Sci & Technol, Key Lab Optoelect Devices & Syst, Minist Educ & Guangdong Prov,Coll Optoelect Engn, Shenzhen 518060, Peoples R China.;Aston Univ, Sch Engn & Appl Sci, Aston Inst Photon Technol, Birmingham B4 7ET, W Midlands, England.
关键词：
Bright solitons;Dark solitons;Graded index fibers;Nonlinear effects;Space division multiplexing;Wave propagation
摘要：
In this paper, we illustrate how the periodically modulated nonlinear parameter induced by the spatial beam oscillation can be used to generate broadband resonant radiations, through a train of dark pulses in normally dispersive graded-index multimode fibers under the efficient quasi-phase-matching schemes. More precisely, we demonstrate that two co-propagating waves with equal intensities and certain temporal delays can induce the formation of a train of dark solitons, with each emitting multiple resonant radiation lines, which can possibly form multiple radiation continuums based on vast amount of excited dark solitons. The nonlinear-interaction-aided excitation of dark pulses and their radiations appear to occur through a deterministic pathway, in sharp contrast to the situation for bright pulses in the anomalous dispersion region. The quasi-phase-matching condition via periodic oscillation of spatial beam in the normal-dispersion regime adds a unique dimension to the physical design of multimode waveguides, allowing the spectrum to be engineered for specific applications. (C) 2019 Optical Society of America under the terms of the OSA Open Access Publishing Agreement
摘要：
Breathing solitons, as localized wave packets with a periodic evolution in amplitude and duration, are able to model extreme wave events in complex nonlinear dispersive systems. We have numerically studied the formation and manipulation of graded-index breathing solitons embedded in nonlinear multimode fibers based on a single nonlinear Schrodinger equation that includes the spatial self-imaging effect through a periodically varying nonlinear parameter. Through changing specific parameters of the input optical field, we can manipulate the period and depth of graded-index breathing soliton dynamics under different relative strengths between the dispersion length and the self-imaging period of the multimode fiber. Our study can explicitly derive a robust mechanism to control the behavior of the breathing localized structure directly and contribute to a better understanding of the much more complex nonlinear graded-index soliton dynamics in multimode fibers.
关键词：
All optical signal processing;Bright solitons;Dark solitons;Phase modulation;Phase shift;Raman scattering
摘要：
We propose a manipulation approach to vary the wave speed, as well as the grayness, of dark solitons under the optical event horizon arising from the interaction between a dark soliton and a probe wave. To the best of our knowledge, the optical event horizon effect is demonstrated for the first time to be capable of inducing a reversible conversion between a black soliton and a gray one. This reversible soliton transformation and control process originates from the intrinsic competition between the probe-induced nonlinear phase shift and the internal phase of the dark soliton. In a cascaded system consisting of two optical event horizons, we also observe the new optical soliton tunneling phenomena where a dark soliton can be reset longitudinally purposely. The results may find applications in information cloaking such as effectively hiding the presence of intermediate fiber section to the receiver.
摘要：
We show that the group-velocity-led optical event horizon (OEH) in optical fibers provides a convenient way to actively control the propagation property of higher-order solitons by a comparatively weak dispersive wave (DW) pulse. It has been found numerically that clean soliton breakup, a process by which a second-order soliton completely splits into a pair of constituent solitons with vastly different power proportions after interacting with the weak DW pulse, will occur while external DWs become polychromatic. The temporal separation between both constituent solitons can be controlled by adjusting the power of the external DW. The more energetic main soliton is advanced/trailed in time depending on the selected frequency of input DW pulse. We have developed an analytic formalism describing the external acting-force (AF) perturbation. These results provide a fundamental explanation and physical scaling of optical pulse evolution in optical fibers and can find applications in improved supercontinuum sources.
摘要：
Finite-difference time-domain (FDTD) method is employed to study the optical properties of a novel kind of periodic subwavelength hole arrays composed of Tai-chi-shaped holes in silver film, and the optical transmission properties of femtosecond optical pulse excitation is numerically calculated. We find that this Tai-chi-shaped device has better optical band-pass filtering properties, such as narrower pass band and higher transmissivity in visible wavelengths range, than other devices under consideration. Based on the generation of surface plasmons resonance mode in the dielectric-metal interface, the center wavelength of transmission can be tuned by changing the array periodicities. We observe that the tune ability mainly depends on the space period along the direction parallel to that of the incident pulse polarization. It is also found that both the strength and the wavelength of the transmission peaks of rectangularly distributed metal hole arrays are determined by the polarization of incident light. Additionally, we demonstrate the typical band-pass filtering properties of this Tai-Chi-shaped holes structure. The full-width at half-maximum (FWHM) of the narrow pass band is about 20 nm in visible wavelengths range. (C) 2014 Elsevier B.V. All rights reserved.
