Study On The Transmission Characteristics Of The Double-Layer Semi-Circular Dielectric-Loaded Surface Plasmon Polaritons Waveguide

As an emerging technological field, integrated optics has been proposed a long time. From the perspective of the science and technology, the main research goal is to study thin film with specific properties and how to use it to make new devices; In the meanwhile, the effect caused by the strong field gathering is also studied. As a result, integrated optical have high requirements for density of the system. Surface plasmons have the ability to break through the subwavelength diffraction limit, which can make the energy of electromagnetic field remain in the nanometer range. The incident light can be restrained and controlled by changing the geometrical structure on the surface of the metal. Nano photonic devices based on surface plasmons is the most promising foundation for nano integrated optical network technology up to now.Surface plasmon waveguide enables optical transmission and field constraints in sub-wavelength level. The primary task is to find the way to controlled field in cross section perpendicular to the direction of propogation while maintaining a relatively low transmission loss.We proposed a new structure that is double-layer semi-circular dielectric-loaded SPPs waveguide in this paper, which works at the wavelength of λ=1550nm. By using the finite element method(FEM), transmission characteristics are analyzed then optimized with the numerical simulation,and the fundamental parameters of this kind of waveguide are also gained. The results show that when the total area of the waveguide remains the same, and the refractive index of the double semi-circular dielectric layers are1 n =1.4 and2 n =1.473 respectively, the transmission characteristics of the waveguide propagation achieve the best. In the foundation of the parameters,when the ratio of the inner and outer semi-circular dielectric’s radius is r1/ r2= 0.5, the maximum propagation length and the minimum attenuation coefficient are achieved; Furthermore, the values of the waveguide’s mode area and the figure of merits become ideal, thus the waveguide transmission characteristics can obtain the optimum effect. This new type of waveguide structure has certain reference and application value in the design of high-density photonic integrated circuits.