In this study, we extend the rigidity and resonance of benzobisthiazo- le for the application as second-order nonlinear optics. A novel nonlinear optical polyimide (NLO-PI) containing side-chained benzobisthiazole- based chromophore has been synthesized. A hydroxyl- containing PI (PHI) was first prepared using direct thermal imidization of 2,4-diaminophenol dihydrochloride and 4,4¡¦-(hexafluoroisopropylidene)diphthalic anhydride; the benzobisthiazole-based chromophore was then prepared using 2,5-diamino- 1,4-benzenedithiol dihydrochloride as the starting monomer. The final NLO-PI was obtained by the Mitsunobu reaction via ether linkage between PHI and the chromophore. This ether linkage is expected to provide chain flexibility for better orientation under electric field during poling. Formation of benzobisthiazole-based chromophore and the corresponding NLO-PI was evidenced by FTIR and UV-vis spectra. TGA and TMA reveal a thermal decomposition temperature and a glass transition temperature as high as 576 and 324oC, respectively. The electrooptic coefficient of the NLO-PI at a wavelength of 630nm was found to be r33 = 6.62 pm/V.

京都大学 / 0048 / 新制・論文博士 / 博士(工学) / 乙第13098号 / 論工博第4159号 / 新制||工||1677(附属図書館) / (主査)教授 中條 善樹, 教授 秋吉 一成, 教授 古賀 毅 / 学位規則第4条第2項該当 / Doctor of Philosophy (Engineering) / Kyoto University / DGAM

The Silicon Wafer Integrated Fiber Technology, SWIFT, is a novel platform for the development of photonic devices. SWIFT is comprised of an optical fiber, specifically a D-fiber in this work, embedded into a V-groove etched into a silicon wafer. This provides a method to secure the fiber and allows the use of standard semiconductor industry equipment and techniques in latter processing for device fabrication. The SWIFT platform is used as the basis for the development of a polarimetric in-fiber electro-optic modulator. The modulator is based on the application of a nonlinear optical polymer, NLOP, film into the evanescent field of a D-fiber. In this way electric fields applied to the NLOP can be used to influence the light propagating through the fiber. The two initial processes in fabricating the modulator are accessing the evanescent field of the D-fiber and making a nonlinear optical polymer (NLOP) thin film. To expose the evanescent field the fiber is chemically etched using hydrofluoric acid. During the etching, light transmitted through the fiber is monitored for changes in power and polarization. The measured optical changes are correlated to scanning electron microscope images of the etched fibers to relate the etch depth to the changes in power and polarization. This provides an etching process that is controllable and repeatable. The NLOP films are made from a simple guest-host system based poly(methyl methacrylate) (PMMA) and dispersed red 1 azo dye (DR1), a nonlinear optical dye. The films are poled to align the dye molecules so that the polymer will exhibit nonlinear optical properties. The poled polymers are tested for second harmonic generation, SHG, to insure that they are nonlinearly optically active. Utilizing the SWIFT platform and the monitored etching process, fibers were etched to a desired 0.2 microns from the core on a repeatable basis. A nonlinear optical polymer was synthesized, formed into thin films, and poled. Nonlinear optical activity in the films was verified by SHG testing.