The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the sup...The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the superposition of LSEx modes rather than TE and TM modes in the mode-matching procedure. Meanwhile, the electromagnetic problem is transferred into the network problem through the mode-matching treatment. It is shown that the present method has the advantages of simplicity and less computation without affecting the accuracy of the calculation.展开更多
An exact solution based on the wavenumber integration method is proposed and implemented in a numerical model for the acoustic field in a Pekeris waveguide excited by either a point source in cylindrical geometry or a...An exact solution based on the wavenumber integration method is proposed and implemented in a numerical model for the acoustic field in a Pekeris waveguide excited by either a point source in cylindrical geometry or a line source in plane geometry. Besides, an unconditionally stable numerical solution is also presented, which entirely resolves the stability problem in previous methods. Generally the branch line integral contributes to the total field only at short ranges, and hence is usually ignored in traditional normal mode models. However, for the special case where a mode lies near the branch cut, the branch line integral can contribute to the total field significantly at all ranges. The wavenumber integration method is well-suited for such problems. Numerical results are also provided, which show that the present model can serve as a benchmark for sound propagation in a Pekeris waveguide.展开更多
We fabricated a new type of two-dimensional photonic crystal slab filter. The resonant cavities were directly put into the waveguide arms. The optical transmissions of the filters were measured and the results show th...We fabricated a new type of two-dimensional photonic crystal slab filter. The resonant cavities were directly put into the waveguide arms. The optical transmissions of the filters were measured and the results show that the optimized two-channel filters give good intensity distribution at the output ports of the waveguide. A minimum wavelength spacing of 5 nm of the filter outputs is realized by accurately controlling the size of the resonant cavities.展开更多
针对光通信系统中光分路器的优化设计问题,提出一种在附加损耗和信道均匀性上性能优良的参数设计方案。基于Opti BPM仿真软件,采用Y分支波导结构设计平面波导型1×4光分路器,分别在不同的芯层折射率和包层折射率下进行仿真,分析得...针对光通信系统中光分路器的优化设计问题,提出一种在附加损耗和信道均匀性上性能优良的参数设计方案。基于Opti BPM仿真软件,采用Y分支波导结构设计平面波导型1×4光分路器,分别在不同的芯层折射率和包层折射率下进行仿真,分析得到了相应的性能变化规律,包括附加损耗、信道均匀性等;并讨论了采用隔离波导的结构设计对1×4光分路器性能的影响。通过研究分析,将不同条件下的最佳参数及结构进行整合优化,最终得到最佳的设计结构参数,包层折射率为1.478、芯层折射率为1.484时,其附加损耗为1.47 d B,信道均匀性可到0.019 d B。这种优化设计下的光分路器均匀性好、结构简单、易于制造,可以在对均匀性要求较高的系统中得到广泛应用。展开更多
An optimization approach based on the genetic algorithms(GAs)for Eplane branch-waveguide couplers is proposed in this paper. The GAs optimization strategies are discussed in detail. A design example for 4-port 5-branc...An optimization approach based on the genetic algorithms(GAs)for Eplane branch-waveguide couplers is proposed in this paper. The GAs optimization strategies are discussed in detail. A design example for 4-port 5-branch 5-dB waveguide couplers is presented. Meanwhile,in this example,some results simulated by the HFSS software,which based on GAs optimization, and other results synthesized by the equivalent-network technique are all presented. Based on the comparison of these results, we find that the results optimized by GAs satisfy the expected requirements. The frequency responses of the couplers with this optimization are improved obviously.展开更多
阐述了3 dB分支波导定向耦合器、波导—微带双探针过渡、改进型波导T型结的原理,介绍了一种4路功率分配/合成网络。提出了一种8路功率分配/合成器,其结构具有插入损耗低、输入驻波好、幅度相位一致性好等优点。研制了50 W Ka频段固态功...阐述了3 dB分支波导定向耦合器、波导—微带双探针过渡、改进型波导T型结的原理,介绍了一种4路功率分配/合成网络。提出了一种8路功率分配/合成器,其结构具有插入损耗低、输入驻波好、幅度相位一致性好等优点。研制了50 W Ka频段固态功率放大器,由驱动级放大器、8路功率分配/合成器和8个7 W功放模块组成,在29~31 GHz频率范围内实现了大于50 W的线性输出功率,合成效率高于80%。展开更多
文摘The E-plane waveguide branch directional couplers are analyzed by a method which combines the multimode network theory with rigorous mode-matching approach. The electromagnetic field components are expanded by the superposition of LSEx modes rather than TE and TM modes in the mode-matching procedure. Meanwhile, the electromagnetic problem is transferred into the network problem through the mode-matching treatment. It is shown that the present method has the advantages of simplicity and less computation without affecting the accuracy of the calculation.
基金supported by the National Natural Science Foundation of China(Grant No.11125420)the Knowledge Innovation Program of the Chinese Academy of Sciences+2 种基金the China Postdoctoral Science Foundation(Grant No.2014M561882)the Doctoral Fund of Shandong ProvinceChina(Grant No.BS2012HZ015)
文摘An exact solution based on the wavenumber integration method is proposed and implemented in a numerical model for the acoustic field in a Pekeris waveguide excited by either a point source in cylindrical geometry or a line source in plane geometry. Besides, an unconditionally stable numerical solution is also presented, which entirely resolves the stability problem in previous methods. Generally the branch line integral contributes to the total field only at short ranges, and hence is usually ignored in traditional normal mode models. However, for the special case where a mode lies near the branch cut, the branch line integral can contribute to the total field significantly at all ranges. The wavenumber integration method is well-suited for such problems. Numerical results are also provided, which show that the present model can serve as a benchmark for sound propagation in a Pekeris waveguide.
基金Project supported by the National Key Basic Research and Development Programme of China （Grant No 2001CB6104）, the National Center for Nanoscience and Technology, China （Grant No 2003CB7169） and the National Natural Science Foundation of China （Grant No 10474036）.
文摘We fabricated a new type of two-dimensional photonic crystal slab filter. The resonant cavities were directly put into the waveguide arms. The optical transmissions of the filters were measured and the results show that the optimized two-channel filters give good intensity distribution at the output ports of the waveguide. A minimum wavelength spacing of 5 nm of the filter outputs is realized by accurately controlling the size of the resonant cavities.
文摘针对光通信系统中光分路器的优化设计问题,提出一种在附加损耗和信道均匀性上性能优良的参数设计方案。基于Opti BPM仿真软件,采用Y分支波导结构设计平面波导型1×4光分路器,分别在不同的芯层折射率和包层折射率下进行仿真,分析得到了相应的性能变化规律,包括附加损耗、信道均匀性等;并讨论了采用隔离波导的结构设计对1×4光分路器性能的影响。通过研究分析,将不同条件下的最佳参数及结构进行整合优化,最终得到最佳的设计结构参数,包层折射率为1.478、芯层折射率为1.484时,其附加损耗为1.47 d B,信道均匀性可到0.019 d B。这种优化设计下的光分路器均匀性好、结构简单、易于制造,可以在对均匀性要求较高的系统中得到广泛应用。
文摘An optimization approach based on the genetic algorithms(GAs)for Eplane branch-waveguide couplers is proposed in this paper. The GAs optimization strategies are discussed in detail. A design example for 4-port 5-branch 5-dB waveguide couplers is presented. Meanwhile,in this example,some results simulated by the HFSS software,which based on GAs optimization, and other results synthesized by the equivalent-network technique are all presented. Based on the comparison of these results, we find that the results optimized by GAs satisfy the expected requirements. The frequency responses of the couplers with this optimization are improved obviously.
