Studies On Micro/nano Photonic Waveguides And Functional Devices

With the rapid developments of very-large-scale integration (VLSI), the degree ofelectronic circuits almost approach the integration limit. Therefore, people hope toreplace (at least in part) electronic circuits by photonic circuits to get higher speedinformation delivering and processing. In the past two decades, all-optical and hybridphotonic-electronic integration circuits have developed rapidly based on theprogressing of the micro/nano photonics functional devices. However, currentmicro/nano waveguides and devices still can’t meet the requirements of the photonicintegration and further researches are needed for the scientists and researchers. In thisthesis, several micro/nano photonic waveguides and functional devices are proposedand designed which we hope can be used in the future large-scale photonic integration.The main contents of this dissertation are as follows:1. Based on the theorem of light enhancement in slot waveguides, we proposed twotypes of low-index guided and confined micro/nano fibers (MNFs) which are ringslot MNF and elliptical slot MNF. By taking advantage of the azimuthal TM01mode, the ring slot MNF can confine light inside the low-index ring region withhigh power confinement efficiency. Except high low-index confinement of HE11mode, the elliptical MNF still have high birefringence. Both ring and ellipticalslot MNFs have properties of low-index field enhancement and nonlinearityenhancement.2. Slow light in conventional periodic dielectric waveguide (PDW) is studied firsttime. The calculated results show that PDWs have guiding modes of low groupvelocity, low group velocity dispersion and high delay-bandwidth product bothfor TE and TM polarization. Highly dispersive ring cavity has been designed byPDWs and its use in lowering the threshold of optical bistability is discussed.3. The birefringence of photonic crystal (PhC), polarization independent self-collimating PhC, and PDW is studied in details. Based on these three micro/nanostructures, we designed broadband (>100nm) achromatic low-order wave plateswith high phase accuracy (±0.01π). High-order (>500) wave plates are also beenproposed by the method of effective birefringence.4. The polarization and wavelength channel drop filter (PW-CDF) is proposed byPhC resonator and waveguide system. Two types of PW-CDF are designed withdifferent resonance systems, one of which has two cavities with single monopole mode and the other has single cavity with two degenerate modes. The designedPW-CDF can fulfill hybrid function of polarization beam splitter and channeldrop filter at the operating wavelength. Besides, a new kind of polarizationbandpass filter (P-BPF) are proposed by one dimensional (1D) PhCheterostructure. The essential function of P-BPF is realized by making the firsttransmitted peak near the photonic bandgap edges of one PhC coincide with thatof the other PhC. Based on this method, three kinds of P-BPFs are designedwhich are isotropic1D PhC single-polarization bandpass filter (SP-BPF) atoblique incidence, anisotropic1D PhC SP-BPF at normal incidence andanisotropic1D PhC double-polarization bandpass filter (DP-BPF) at obliqueincidence.