Research On Multi-channel Splitter Based On Two-dimensional Photonic Crystals Waveguide

With the development of science and technology,the requirements of information demand and processing speed are becoming higher and higher.It is difficult to meet the communication network composed of electronic circuit devices as the carrier.Therefore,passive device has become the current research hotspot.Among which optical beam splitter is one of the most important devices.Photonic crystal,as a new material,has become one of the important materials for fabrication of optical passive devices due to its unique band gap characteristics and local characteristics,attracting the attention of many researchers at home and abroad.In this paper,a 1×5 equal proportion beam splitter and a 1×4terahertz beam splitter with tunable optical control ratio are designed based on the basic characteristics of photonic crystal.The specific work is as follows:(1)Based on the coupling characteristics of point and line defects in photonic crystal,a 1×3fixed proportion beam splitter and a 1×5 equal proportion beam splitter based on two-dimensional photonic crystal waveguide in communication band are proposed.Using Rsoft software,combined with the plane wave expansion method(PWM)and the finite difference time domain method(FDTD),the simulation analysis and performance research of two kinds of splitters are carried out.The results show that: in the 1×3 fixed proportion beam splitter based on photonic crystal waveguide,with the change of point defect radius,the total transmittance of the three output ports is more than 92.2%,and the additional loss is less than 0.353 d B;In the 1×5 equal proportion beam generator based on photonic crystal waveguide,the transmittance of 5 output ports is 19.93%,the total transmittance is99.65% and the additional loss is 0.015 d B.(2)Based on the bandgap and local characteristics of photonic crystal,a 1×4 terahertz beam splitter based on photonic crystal waveguide and a 1×4 beam splitter with photocontrolled spectral ratio tunable are proposed.Using Rsoft software,combined with the plane wave expansion method(PWM)and the finite difference time domain method(FDTD),the simulation analysis and performance research of two kinds of terahertz beam splitters are carried out.The results show that:in the 1×4 terahertz beam splitters based on photonic crystal waveguides,a splitter with the Angle of60 degrees has the best performance,with a total transmittance of 99.50% and additional loss of0.022 d B.In the 1×4 terahertz beam splitter with adjustable optical splitter ratio based on photonic crystal waveguide,the adjustable optical splitter ratio can be realized in the range of 1.9 ～10,the total transmittance is 97.6%,and the additional loss is 0.106 d B.