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1

Controllable wavelength conversion based on soliton dynamics in mid-infrared fiber

Shen Kangle, Yang Jian, Zhao Jiayi, Yang Xinyu, Yang Hua

Optica Applicata

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2023

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Vol. 53, nr 3

419--429

EN

We provide a convenient way to actively control the wavelength conversion of probe waves based on the soliton dynamics in the As2S3 fibers. In this paper, it is found by numerical calculation that wavelength conversion occurs in the frequency domain due to the existence of refractive index barrier. By adjusting the collision position of pump pulse and probe pulse to realize the conversion of probe pulse wavelength, the effect of the power and the incident wavelength of the probe wave on the wavelength conversion are also discussed. This frequency domain conversion is of great use in the mid-infrared region, for example, all-optical conversion switches.

2

Photovoltaic power prediction based on improved grey wolf algorithm optimized back propagation

He Ping, Dong Jie, Wu Xiaopeng, Yun Lei, Yang Hua

Archives of Electrical Engineering

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2023

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Vol. 72, nr 3

613--628

EN

At present, the back-propagation (BP) network algorithm widely used in the short-term output prediction of photovoltaic power stations has the disadvantage of ignoring meteorological factors and weather conditions in the input. The existing traditional BP prediction model lacks a variety of numerical optimization algorithms, such that the prediction error is large. The back-propagation (BP) neural network is easy to fall into local optimization thus reducing the prediction accuracy in photovoltaic power prediction. In order to solve this problem, an improved grey wolf optimization (GWO) algorithm is proposed to optimize the photovoltaic power prediction model of the BP neural network. So, an improved grey wolf optimization algorithm optimized BP neural network for a photovoltaic (PV) power prediction model is proposed. Dynamic weight strategy, tent mapping and particle swarm optimization (PSO) are introduced in the standard grey wolf optimization (GWO) to construct the PSO–GWO model. The relative error of the PSO–GWO–BP model predicted data is less than that of the BP model predicted data. The average relative error of PSO–GWO–BP and GWO–BP models is smaller, the average relative error of PSO–GWO–BP model is the smallest, and the prediction stability of the PSO–GWO–BP model is the best. The model stability and prediction accuracy of PSO–GWO–BP are better than those of GWO–BP and BP.

3

Fully negative near-zero ultra-flat dispersion photonic crystal fibers in E+S+C+L band

Mao Yucheng, Ma Yiwu, Huang Ying, Yang Hua

Optica Applicata

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2022

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Vol. 52, nr 4

599--611

EN

We demonstrate a modified hexagonal three-layer air-hole photonic crystal fiber (PCF) which presents a good ability of dispersion management. The proposed PCF not only achieved an ultra-flattened all-negative dispersion characteristics of 0.15085 ps/(km·nm) fluctuation within the wavelength range of E+S+C+L wavelength band but also has been able to obtain other interesting features such as low confinement loss. Furthermore, the quadrilateral and octagonal structures are investigated to compare the superiority of different structures and analyze why we chose the hexagonal one.

4

Influence of dispersion slope on soliton spectral tunneling in photonic crystal fiber

Yang Yunxia, Yang Hua, Tong Xiongfeng, Zhao Saili, Chen Shuyuan

Optica Applicata

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2021

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Vol. 51, nr 3

415--427

EN

We report a numerical investigation of how the dispersion slope affects the soliton spectral tunneling (SST) in a photonic crystal fiber with three zero dispersion wavelengths. It is discovered that a larger dispersion slope makes group-velocity mismatch between the initial soliton and the transferred wave thereby suppressing the SST effect, while a proper decrease of the dispersion slope enhances the SST effect to widen a supercontinuum range. Besides, we find a soliton-like leaking dispersion wave, which can sustain information and energy for a short time within a particular spectral range.

5

Computation and experimental comparison of the deformation behavior of pantographic structures with different micro-geometry under shear and torsion

Yang Hua, Müller Wolfgang H.

Journal of Theoretical and Applied Mechanics

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2019

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Vol. 57 nr 2

421--434

EN

Additive manufacturing methods, commonly known as 3D printing, allow more sophisticated designs to be created. Willingly designed substructures incorporated into the solid open up new possibilities for uncommon macroscopic deformation behavior. Such a man-made structure is also referred to as a metamaterial. A detailed simulation of a polymer-based metamaterial is challenging but accurately possible by means of the theory of elasticity. In this study, we present experimental investigations of a metamaterial composed of pantographic substructures of different internal geometry. The pantographic structures show an unexpected type of deformation, which can be modeled via elasticity with the aid of direct numerical simulation by using the Finite Element (FE) method. In other words, a detailed mesh is generated involving the substructure. The metamaterial is additively manufactured out of a common polymer showing nonlinear elastic deformation and, therefore, hyperelastic material models are used. Specifically, analytical solutions of a circular cylinder are examined and compared in the case of extension and torsion in order to comprehend the effects of the coefficients inherent to the energy function of the hyperelastic model. Finally, FE computations of pantographic structures are performed and compared with the experimental measurements.