Research On The Mechanism And Applications Of Waveguide With Periodic Electromagnetic Structure

With the development of internet of things,5G communications,artificial intelligence and high-performance computing,photonic integrated circuit(PIC)has become the technical foundation of various new information systems due to its high speed,big capacity and low loss characteristics.As the key components of the photonic integrated devices(PIDs),waveguide material and device structure play an important role in PID's function expansion and performance improvement.Periodic electromagnetic structure(PEMS)waveguide has the advantages of flexible structure design,diverse material selection and strong electromagnetic control ability,which provides a new technical approach for the development of multi-function PIDs with small size and high performance.This dissertation focuse on the miniaturization and multifunction of polarization controlling device and on-chip waveguide laser which based on the functional integration of PEMs waveguide and advanced waveguide materials.The major research works are summarized as follows.Firstly,the basic working principles of PEMS waveguide are elaborated,the general form of the coupled-mode equations and the analytic expression of the key parameters is given.The equivalent refractive index and mode characteristics of the subwavelength PEMS waveguide are analyzed and discussed in detail.The numerical analysis methods used in this dissertation are introduced to provide a theoretical basis foundation for the design of PEMS devices.Secondly,the birefringence phenomenon of silicon-on-insulator platform are systematically analyzed and three types of PEMS-based polarization controlling devices have been proposed.A compact TM-pass/TE-divide polarization beam splitter using contra-directional grating couplers assisted by horizontal slot waveguide is proposed.The optimized length of the coupling region is 14?m and the extinction ratios of TE and TM mode at the central wavelength are 38.4 dB and 20.9 dB,respectively.An ultra-broadband TE-pass polarizer based on hybrid plasmonic-assisted contra-directional grating couplers is designed.The device is 16.48?m long and the working bandwidth is 270 nm.An interleaved subwavelength gratings strip waveguide based TM-pass polarizer of 5.2?m in length is presented,the operation bandwidth for extinction ratio over 20 dB and insertion loss below 0.32 dB is 155 nm.Compared with some previous reports,these three polarization controlling devices have obvious advantages.Then,the carbon materials based PEMS polarization controlling devices are investigated.A22.2?m long polarization beam splitter is designed by using subwavelength grating-assisted directional coupler structure on diamond-on-insulator platform.This device working bandwidth covers the whole O-band and can make a contribution to the polarization controlling in the integrated quantum optical networking.By using graphene/SiO₂multilayer film stack structure PEMS metamaterial,an ultra-compact low loss TE pass polarizer is realized.Simulation results show that the insertion loss and extinction ratio at central wavelength of this polarizer are 0.228dB and 15.99 dB,respectively.Next,a design scheme of distributedBragg reflector Er³⁺/Yb³⁺co-doped Al₂O₃ waveguide laser is presented in this dissertation,which consists of a bend gain waveguide and two identical Bragg gratings waveguides.The Er³⁺/Yb³⁺co-doped Al₂O₃ thin films are prepared by the magnetron sputtering method.The effects of annealing temperature on films structural properties and photoluminescence characteristics are systematically investigated.Experimental results show that the films have the best crystallinity,orderly lattice structure and the strongest photoluminescence intensity when the annealing temperature is 850?.Finally,the conclusion of the whole dissertation and the prospect of the future work is given.