In this paper, we consider electromagnetic scattering problems for two-dimensional overfilled cavities. A half ringy absorbing perfectly matched layer （PML） is introduced to enclose the cavity, and the PML formulati...In this paper, we consider electromagnetic scattering problems for two-dimensional overfilled cavities. A half ringy absorbing perfectly matched layer （PML） is introduced to enclose the cavity, and the PML formulations for both TM and TE polarizations are presented. Existence, uniqueness and convergence of the PML solutions are considered. Numerical experiments demonstrate that the PML method is efficient and accurate for solving cavity scattering problems.展开更多
We present a theoretical analysis of corrugated long-period gratings in planar waveguides. In particular, we calculate the transmission spectra for both the TE and TM polarizations and highlight the polarization-indep...We present a theoretical analysis of corrugated long-period gratings in planar waveguides. In particular, we calculate the transmission spectra for both the TE and TM polarizations and highlight the polarization-independence conditions.展开更多
Based on the traditional directional coupler, we proposed a scheme to design on-chip polarization beam splitters using an inverse design method. In our scheme, the coupling area of the designed devices are only 0.48 ...Based on the traditional directional coupler, we proposed a scheme to design on-chip polarization beam splitters using an inverse design method. In our scheme, the coupling area of the designed devices are only 0.48 μm× 6.4 μm. By manipulating the refractive index of the coupling region, the devices can work in C-band,L-band, O-band, or any other communication band. Different from conventional design methods, which need to adjust the design parameters artificially, if the initial conditions are determined, the proposed scheme can automatically adjust the design parameters of devices according to specific requirements. The simulation results show that the insertion losses of the designed polarization beam splitters can be less than 0.4 dB(0.35 dB) for TE(TM)mode at the wavelengths of 1310, 1550, and 1600 nm, and the extinction ratios are larger than 19.9 dB for the TE and TM modes at all three wavelengths. Besides, the extinction ratios of both polarization states are more than 14.5 dB within the wavelength range of 1286–1364 nm, 1497–1568 nm, and 1553–1634 nm. At the same time,the insertion losses are smaller than 0.46 dB.展开更多
This study has proposed and numerically demonstrated a compact terahertz wave polarization beam splitter. The splitter is built by using a asymmetrical directional coupler consisting of a bend waveguide and a slot ben...This study has proposed and numerically demonstrated a compact terahertz wave polarization beam splitter. The splitter is built by using a asymmetrical directional coupler consisting of a bend waveguide and a slot bend waveguides and achieves a high extinction ratio of 24.88 dB and 16.55 dB for cross and through ports. The optimal coupling region length is found to be 26 ttm. By using such a polarization beam splitter, the size of the terahertz wave system could he reduced significantly. The simulation results show that the designed polarization beam splitter can split TE- and TM-polarized terahertz wave into different propagation directions with high efficiency over the terahertz wave frequency range from 9.40 THz to 9.65 THz. The device obtained is readily used for a polarization diversity terahertz wave integrated circuit field, particularly for platforms with slot waveguide.展开更多
文摘In this paper, we consider electromagnetic scattering problems for two-dimensional overfilled cavities. A half ringy absorbing perfectly matched layer （PML） is introduced to enclose the cavity, and the PML formulations for both TM and TE polarizations are presented. Existence, uniqueness and convergence of the PML solutions are considered. Numerical experiments demonstrate that the PML method is efficient and accurate for solving cavity scattering problems.
文摘We present a theoretical analysis of corrugated long-period gratings in planar waveguides. In particular, we calculate the transmission spectra for both the TE and TM polarizations and highlight the polarization-independence conditions.
基金National Natural Science Foundation of China(NSFC)(60907003)Natural Science Foundation of Hunan Province(13JJ3001)+1 种基金Program for New Century Excellent Talents in University(NCET)(NCET-12-0142)Foundation of NUDT(JC13-02-13)
文摘Based on the traditional directional coupler, we proposed a scheme to design on-chip polarization beam splitters using an inverse design method. In our scheme, the coupling area of the designed devices are only 0.48 μm× 6.4 μm. By manipulating the refractive index of the coupling region, the devices can work in C-band,L-band, O-band, or any other communication band. Different from conventional design methods, which need to adjust the design parameters artificially, if the initial conditions are determined, the proposed scheme can automatically adjust the design parameters of devices according to specific requirements. The simulation results show that the insertion losses of the designed polarization beam splitters can be less than 0.4 dB(0.35 dB) for TE(TM)mode at the wavelengths of 1310, 1550, and 1600 nm, and the extinction ratios are larger than 19.9 dB for the TE and TM modes at all three wavelengths. Besides, the extinction ratios of both polarization states are more than 14.5 dB within the wavelength range of 1286–1364 nm, 1497–1568 nm, and 1553–1634 nm. At the same time,the insertion losses are smaller than 0.46 dB.
基金supported by the Zhejiang Province Natural Science Foundation for Distinguished Young Scientists under Grant No.LR12F05001the National Natural Science Foundation of China under Grant No.61379024 and 61131005
文摘This study has proposed and numerically demonstrated a compact terahertz wave polarization beam splitter. The splitter is built by using a asymmetrical directional coupler consisting of a bend waveguide and a slot bend waveguides and achieves a high extinction ratio of 24.88 dB and 16.55 dB for cross and through ports. The optimal coupling region length is found to be 26 ttm. By using such a polarization beam splitter, the size of the terahertz wave system could he reduced significantly. The simulation results show that the designed polarization beam splitter can split TE- and TM-polarized terahertz wave into different propagation directions with high efficiency over the terahertz wave frequency range from 9.40 THz to 9.65 THz. The device obtained is readily used for a polarization diversity terahertz wave integrated circuit field, particularly for platforms with slot waveguide.
