中文摘要：

当今,随着社会信息化程度的不断提高,人们对高速率、实时通信和便携微型化的通信要求越来越强烈。为了实现光子器件的高集成度的要求,将信号局域在亚波长尺寸内,文章采用表面等离子体波导来设计亚波长尺寸的解复用器;表面等离子体是由光的模场激发的电子的集体振荡,并在金属和介质表面传播的一种电子疏密波,它能将光局域到亚波长尺寸;文章的解复用器的横向尺寸为620 nm,远远小于工作波长1550 nm。布拉格光栅是一种光子带隙结构,在表面等离子体波导结构中利用这种光子带隙结构可以实现较高隔离度的信号解复用。同时运用（Finite-Difference Time-Domain Method,FDTD）算法对设计的表面等离子体布拉格光栅解复用器进行模拟仿真,并利用耦合模理论和光子带隙理论做相应的理论分析。结果表明,表面等离子体光栅带隙结构的解复用器具有很高的隔离度,能比其他解复用器具有更好的隔离信号串扰的能力。模拟在1550 nm波长附近的隔离度可达27.5 db。基于光子带隙结构的表面等离子体解复用器具有高集成、高隔离度、低损耗等特性,具有很好的应用前景。

英文摘要：

Nowadays, with the continuous improvement of information technology, people’s requirement on high-speed, real-time communication and miniaturization of portable communications become stronger and stronger. In order to meet the high integrated requirement for future photonic device, it requires the optical mode to be localized in the size of sub-wavelength. In the paper, the surface plasmon polaritons waveguide was used to design the demultiplexer with sub-wavelength size. Governed by the diffraction limit, the traditional photonic device cannot transmit optical signal in sub-wavelength size waveguide. Surface plasmon polaritons（SPPs） was collective electron oscillation caused by the electromagnetic modes, which propagate alone a metal-dielectric interface. It has been considered as a solution to overcome the diffraction limit. In the paper, the device lateral dimension was about 620 nm, much smaller than the transmission wavelength 1550 nm. The bragg grating was a kind of photonic band gap structure. When this structure is added into the SPPs waveguide, the purpose of distinguishing the signal from the others with high extinction ratio can be realized. The finite-difference time-domain（FDTD） method with perfectly matched layer absorbing boundary conditions is used to get the mode field distribution,and use the coupled-mode theory and theory of photonic band gap to theoretical analysis. The results showed that the band structures of surface plasmon Bragg grating demultiplexing equipment has a high degree of isolation. So, it has the ability to better isolate the signal crosstalk than other solution. At the same time, it has lower insertion loss. The simulation result revealed that the extinction ration can reach to 27.5 db in the wavelength of 1550 nm. The novel integrated demultiplexer proposed in this paper with the high level of integration, high extinction ratio and low intrinsic loss. So, it is bound to have an excellent future of application.