Study On Coupling Nano-SOI Waveguide With Optical Fiber

Silicon photonic circuit based on Silicon-on-insulator(SOI)nanometer waveguide owns a great prospective in monolithic electro-optical integration.Due to its transparency in C-band,large refractive index difference and fully compatibility with the standard CMOS(Complementary-Metal-Oxide-Semiconductor)technology,it is suitable for large scale's manufacture and integration.The efficient coupling between Si nano waveguide and optical fiber is one of the problems which must be solved for practical use.The thesis aims at sovling the problem of high efficiency coupling between nano-SOI waveguide and optical fiber.We come up with the system structure of coupling nano-SOI waveguide with optical fiber with self-auto alignment using the V-shape slot and high coupling efficiency using the inverted tapered coupler.Based on the theory of coupling waveguide with optical fiber,we simulate the inverted tapered coupler using FDTD solutions to optimize the device parameter.We design the technological process of the device.The V-shape slot structure and inverted tapered coupler on SOI platform is experimentally realized by nano fabrication technology.The coupling efficiency of 3.5d B per facet is demonstrated in this thesis.The content of the thesis includes two parts.(1)Discuss the basic theory of coupling waveguide with optical fiber.Use FDTD software to simulate the designed inverted tapered coupler in the system structure,to optimizing the parameter of the structure.We come up with the system structure of coupling nano-SOI waveguide with optical fiber with self-auto alignment using the V-shape slot and high coupling efficiency using the inverted tapered coupler.And We design the technological process of the device.(2)Make analysis for the technology results.Use electronic beam lithography(EBL)and induced coupled plasma(ICP)technology to make SOI waveguide and inverted taper.Following,use EBL overlay technology to cover a a cladding layer of SU8 on SOI inverted taper by spin coating 3.8?m SU8 resist on SOI wafer.To avoid facet polishing,useultraviolet(UV)lithography and ICP deep etching technology to make deep rectangular slot near coupling facet,to supply putting space for coupling coupler with optical fiber.We achieve the whole coupler structure and results shows coupling loss is 3.5d B per facet.To solve the problems of aligning optical fiber to coupler,use overlay technology and anisotropic wet etching method on silicon to make V-shape slot.We successfully make silicon V-shape slot,which set a foundation to achieve self-auto-alignment optical coupling.The thesis is focused on coupling SOI waveguide with optical fiber.Use EBL technology to define the cladding waveguide of SOI inverted taper and coupling facet on spin-coated SU8 resist.Use a deep slot near coupling facet to get rid of difficulty of facet polishing and silicon cleaving.Use V-shape slot to solve the problem of aligning optical fiber to coupler.The experiment results offer guidance for increasing the efficiency of coupling nano-SOI waveguide with optical fiber and lowering technological difficulty.