Research Of Electro-optic Modulator Based On Bonded Organic-inorganic Hybrid Materials

The Electro-optic modulator is a key device for optical fiber communicationsystem,it plays an irreplaceable role in the process of optical informationprocessing.As the rapid development of IT and continuous demand of communicationbandwidth, Traditonal modulator has obviously become an bottleneck of thecommunication bandwidth.Demand for high-speed, high bandwidth modulator isincreasingly urgent.Poled polymeric electro-optic modulator,which has advantages offast response, hihg electro-optic coefficient, low dielectric constant, low-cost, easy-integrated, easy to achieve high bandwidth, etc, has attracted many researchers.Organic-inorganic hybrid materials have the advantages of both organic andinorganic materials, it overcomes the defect of stability of pure polymer and becomesan important branch of polymeric electro-optic modulator.In this thesis, the types and significance of optical modulator, the materialclassification of electro-optic modulator, the classification of poled polymer and theresearch progress of electro-optic modulator is introduced firstly. Then the basictheory of polymeric electro-optic modulator including the theory of electro-opticeffect and poled polymeric M-Z electro-optic modulator is discussed. Next thesynthesis and characterization of a novel kind of side-chain bonded organic-inorganichybrid materials was discussed. Then the fabrication of strip-loaded and reversedridge MZ electro-optic modulators was descripted, they are made by the organic-inorganic hybrid materials,then they are poled and tested.The following are the maincontents of this thesis:1、A new type of side-chain bonded organic-inorganic hybrid materials aresynthesized. The synthesis method of hybrid materials includes two steps. For the firststep, the molecules of chromophore DR-19are bonded to the molecules of KH-560through chemical bond,so a kind of alkoxy silane dye material-DR-19ASD aresynthesized;then the synthetic alkoxy silane dye which contains molecules ofchromophore DR-19is hydrolyzed and condensed to get the final side-chain bondedorganic/inorganic hybrid materials by sol-gel method. As the molecules ofchromophore DR-19are connected to the main chain of the hybrid materials by chemical bond and the hybrid materials contain chemical bond of Si-O-Si, Si-O-Tiand Ti-O-Ti,which are inorganic grid. Compared with pure polymer, the hybridmaterials have the advantages of better optical property and stability,higherpercentage of chromophore content, easier synthesis,etc.2、The synthetic hybrid materials is characterized though series of method. Itsfilm-forming property is revealed by atomic force microscopy images;the refractiveindex of hybrid materials at wavelength of1550nm is1.498which is showed by thedata of Ellipsometer measurement; thermal decomposition temperature of the hybridmaterial is fixed on300°C by TGA curve, which suggests good thermal stability; theglassy transition temperature of the hybrid materials is defined with the range of150-290°C by DSC curve;the order parameter value is calculated of0.246throughdata of UV-visible light absorption spectrum measurement of a single-layer hybridmaterials film before and after high-temperature corona poling; the coefficient of theelectro-optic hybrid materials in the wavelength of1310nm is20pm/V afterhigh-temperature corona poling by simple reflection method.3、Using the independently synthesied side-chain bonded organic/inorganichybrid materials,M-Z electro-optic modulators of strip-loaded waveguide structureand reversed ridge waveguide structure are fabricated. The fabrication processincludes spin-coating, lithography, developing, etching,etc. The morphology ofwaveguide is characterized with optical microscopy and scanning electronmicroscopy.Then the devices are poled.For the the strip loaded waveguideelectro-optic modulator, high-temperature corona poling is used, the insertion loss inthe wavelength of1550nm is21dB, sinusoidal modulation response of19KHz,31KHz,50KHz,60KHz are observed; for the reveral ridge waveguide electro-opticmodulator, contact polarization is used, the insertion loss at wavelength of1310nmand wavelength of1550nm are11.3dB and23.1dB,respectively.Correspondingly,atthe wavelength of1550nm, sinusoidal modulation response of10KHz is observed.