A novel ultra-broadband polarization splitter based on a dual-core photonic crystal fiber(DC-PCF)is designed.The full-vector finite element method and coupled-mode theory are employed to investigate the characteristic...A novel ultra-broadband polarization splitter based on a dual-core photonic crystal fiber(DC-PCF)is designed.The full-vector finite element method and coupled-mode theory are employed to investigate the characteristics of the polarization splitter.According to the numerical results,a graphene-filled layer not only broadens the working bandwidth but also reduces the size of the polarization splitter.Furthermore,the fluorine-doped region and the germanium-doped region can broaden the bandwidth.Also,the 4.78 mm long polarization splitter can achieve an extinction ratio of-98.6 d B at a wavelength of 1550 nm.When extinction ratio is less than-20 d B,the range of the wavelength is 1027 nm-1723 nm with a bandwidth of 696 nm.Overall,the polarization splitter can be applied to all-optical network communication systems in the infrared and near-infrared wavelength range.展开更多
In this paper,a numerical investigation about the metal transfer of GMAW is investigated based on the phase field model.Be different of most published work,we take the thermocapillary effect and mixture energy into th...In this paper,a numerical investigation about the metal transfer of GMAW is investigated based on the phase field model.Be different of most published work,we take the thermocapillary effect and mixture energy into the process of phase transfer and interface change which is different from volume of fluid( VOF) method.We discretize the whole model with a continuous finite element method and we also apply a penalty formulation to the continuity condition enhancing the stability of the pressure.Metal transfer of GMAW with constant and pulse current is computed as numerical examples which agrees well with the data of high-speed photography.The result shows that the computing process of the phase field model is stability and it has a higher precision in predicting the diameter of droplet.展开更多
In this paper,based on the finite element formulation,we focus on multiple solutions and their evolution with time for a laminar flow in a permeable channel with expanding or contracting walls.Both Newtonian fluid and...In this paper,based on the finite element formulation,we focus on multiple solutions and their evolution with time for a laminar flow in a permeable channel with expanding or contracting walls.Both Newtonian fluid and micropolar fluid are consid-ered.For the Newtonian fluid model,we find that the profile of the unique solution in the case of injection remains the same for long time,which indicates that the solution may be stable.On the other hand,in the case of large suction,the profile of multiple solutions changes in time,which suggests that the multiple solutions may be unstable.Similar behaviors and conclusions are observed for the micropolar fluid model under different boundary parameters.展开更多
基金Project supported by the State Key Laboratory of Luminescence and Applications(Grant No.SKLA-2020-01)。
文摘A novel ultra-broadband polarization splitter based on a dual-core photonic crystal fiber(DC-PCF)is designed.The full-vector finite element method and coupled-mode theory are employed to investigate the characteristics of the polarization splitter.According to the numerical results,a graphene-filled layer not only broadens the working bandwidth but also reduces the size of the polarization splitter.Furthermore,the fluorine-doped region and the germanium-doped region can broaden the bandwidth.Also,the 4.78 mm long polarization splitter can achieve an extinction ratio of-98.6 d B at a wavelength of 1550 nm.When extinction ratio is less than-20 d B,the range of the wavelength is 1027 nm-1723 nm with a bandwidth of 696 nm.Overall,the polarization splitter can be applied to all-optical network communication systems in the infrared and near-infrared wavelength range.
文摘In this paper,a numerical investigation about the metal transfer of GMAW is investigated based on the phase field model.Be different of most published work,we take the thermocapillary effect and mixture energy into the process of phase transfer and interface change which is different from volume of fluid( VOF) method.We discretize the whole model with a continuous finite element method and we also apply a penalty formulation to the continuity condition enhancing the stability of the pressure.Metal transfer of GMAW with constant and pulse current is computed as numerical examples which agrees well with the data of high-speed photography.The result shows that the computing process of the phase field model is stability and it has a higher precision in predicting the diameter of droplet.
基金This work is partially supported by the National Natural Science Foundations of China(No.91430106)the Fundamental Research Funds for the Cen-tral Universities(No.06500073).
文摘In this paper,based on the finite element formulation,we focus on multiple solutions and their evolution with time for a laminar flow in a permeable channel with expanding or contracting walls.Both Newtonian fluid and micropolar fluid are consid-ered.For the Newtonian fluid model,we find that the profile of the unique solution in the case of injection remains the same for long time,which indicates that the solution may be stable.On the other hand,in the case of large suction,the profile of multiple solutions changes in time,which suggests that the multiple solutions may be unstable.Similar behaviors and conclusions are observed for the micropolar fluid model under different boundary parameters.
