The Design And Research Of Three-Dimensional Optical Waveguide And Device Based On Two Kinds Of Metal Dielectric Waveguide

Surface Plasmon Polaritons(SPPs)are surface electromagnetic waves motivated by the interaction of free electron in metallic surface with environmental photons.Nano device based on SPPs can confine the light into the subwavelength region of the metal surface,and thus break through the diffraction limit of conventional optics and realize nano-level optical transmission and processing.Because of unique properties,SPPs has been widely used in the fields of new energy,sensing and high sensitive biological detection.With the deepening of the research on SPPs,its new photonics device and optical sensing research on micro/nano devices such as field will have broader prospects for development.In this thsis,a three-dimensional plasmonic waveguide(TDPW)is proposed based on the symmetric and asymmetric metal-cladding optical waveguides,the propagation characteristics of TDPW has been investiaged with with effective refractive index method,and then a variety of nanoscle optical based on TDPW devices are designed and studied,in addtion,the optical characteristics in the waveguide and devices is numerically analyized bythe Finite DifferenceTime Domain Method(FDTD).The specific work is as follows:(1)Properties of SPPs propagating in TDPW has been investigated by Effective index method and numerical simulation,and the research method is changing the waveguide geometry parameters including the width wm,and height hm,of the metal Ag,and the thickness td of the dielectric layer of SiO2 with the fixed wavelengths of 1550nm and 635nm.The result demonstrates that SPPs is strongly localized in the core of TDPW.In addtion,the waveguide showed the best performance when the geometrical parameters are wm =80nm,hm=200nm and td=70nm(1550nm),and wm=60nm,hm= 90nm and td= 70nm(635nm).(2)The bending transmission efficiency in the oblique bending and 90° bending based on TDPW is investigated.The SPPs in the waveguide can maintain a good transmission effect in a large bending angle ?,for example,when the incident wavelength is 1550nm1 the transmittance can still reach 74%.For 90° bending,the bending radius of 1550nm in the incident wavelength can achieve non-destructive transmission effect(excluding ohm loss).(3)the dependence of coupling length and coupling efficiency on waveguide spacing is studied in the directional coupling analysis based on TDPW,at the fixed wavelength of 1550nm,and the result shows existing a the minimum coupling length.And then the dependence of the performance of optical discrete diffraction on the waveguide spacing is investigated.(4)Based on TDPW,the ring resonator and Add-Drop Filter are proposed.In theory,the free spectral range(FSR)is inversely proportional to the bending ring radius,that is,the smaller the radius is,the larger the FSR is.FDTD numerical simulation shows that in the same case,the ring resonance frequency and FSR range of the two devices are consistent.(5)By uniformly reducing the width of the TDPW coated metal Ag strips,designed a nanosclelight concentrator is designed,and the width of incident light is fixed at 800 nm.The simulation results show that when the output end reaches saturation,the focus scale can be reduced to 25%of the width of the incident light source.And when the output end focusing spot reaches the maximum output intensity,the focus scale can be further reduced to 10%of the width of the incident light source.(6)Finally,an Mach-Zehnder interferometer based on TDPW is proposed.Based on the principle of optical interference,the interference of the output light can be increased or eliminated by adjusting the refractive index of the single interference arm.