Fabrication And Transmission Properties Research Of SOI Integrated Optical Waveguide

Traditional electronic devices can not meet the requirements of nowadays society largecapacity and high speed requirements for information transmission; optical waveguidetechnology emerged, and became the most potential basic structure of optoelectronicintegrated and photonic devices. SOI waveguide has the advantage of the silicon material,also has a high refractive index contrast, at the same time completely compatible with theCMOS process, so it has great potential application in integrated optoelectronic devices. Withthe development of nano-photonics and micro-processing technology, optoelectronic devicesmonolithically integrated based on SOI material became an important development directionof the photonics industry. High-performance of silicon optical waveguide devices depends onthe ultra-low loss optical waveguide structure unit. The light energy transfer in the form ofevanescent field along the waveguide surface, both the size、transmission modes and surfaceroughness of the waveguide are important factors that can cause loss of optical transmission.Therefore, it has important scientific significance and value to study the transmissioncharacteristics and the preparation process of the SOI waveguide for ultra-low-loss SOIwaveguide. In this thesis, the main work includes：(1) In theory, transmission modes of the SOI waveguide were researched, effectiverefractive index, cutoff of transmission and mode single-mode transmission conditions of SOIrectangular waveguide were analyed in TE mode. SOI waveguide transmission loss types andcharacterization methods are summarized. SOI waveguides single-mode transmissionconditions were simulated with the finite difference time domain method (FDTD), the lightfield distribution and loss of SOI waveguides of different width were simulated. Based ontheoretical and simulation results, Straight waveguide and 90-degree bend waveguide, 180degree bend waveguide, circular waveguide structure were designed.(2) In the fabrication of SOI integrated optical waveguide, the four-inch process technology and the fragmentation process were mainly researched in this paper. The four-inchprocess used UV lithography and inductively coupled plasma etching, focused ion beametching. The minimum width of the waveguide was 1μm . The fragmentation process usedelectron beam lithography, magnetron sputtering and inductively coupled plasma etching, theminimum dimensions of the waveguide 500 nm .(3) In testing, coupling efficiency and transmission loss of SOI waveguides fabricated bydifferent processes were tested in this paper, mainly with the SEM, AFM and optical testplatform. Coupling efficiency of facet coupling and vertical nano-grating coupling were 12%and 47% respectively, and measured transmission loss of two groups SOI rectangularwaveguide were 8.32 dB / cmand 4.67 dB / cm, the bend loss of ring waveguide with radiusof 20μmand width of 500 nm was 0. 02±0.001dB /bend.