Research On The Technique Of Femtosecond Laser Inscription Of Waveguide And Its Application

Optical waveguide is widely used in optic communication and signal processingas one of the most important basic elements. Waveguides can realize photonicsfunction such as data transmission, nonlinear medium and active gain, etc. Comparedto conditional waveguide fabrication technologies, the technology of femtosecondlaser photoinscription of waveguides is essentially a three-dimensional technologywith the advantage of simplicity and flexibility. That technique has shown greatpotential for new complex high-density integrated optical elements. This dissertation,according to the application of integrated optical functional component, report on theremarkable polarization dependent guiding effects stress-induce Ti:Sapphire crystalswaveguide which comprise anisotropic light scattering on periodic nanostructures andstress-induced birefringence in the central zone, fabrication of waveguide on the highnonlinear coefficient heavy metal oxide glass and active gain medium Yb3+-dopedphosphate glass. Meanwhile, the1030nm wavelength output cw-waveguide laser has beensuccessful developed and proved to be stable.The main research works and innovations of this dissertation are summarized asfollows:1. With the femtosecond laser inscription, the Ti:Sapphire crystals waveguideswhich comprise the self-organization of nanoscale material redistributionregions are derived. The laser polarization and energy level impact on themorphology are discussed. The formation of the nanograte is explained withthe transient plasma modal. Due to anisotropic light scattering on periodicnanostructures and stress-induced birefringence in the central zone,remarkable polarization dependent guiding effects were observed as afunction of the microscopic geometry of the structures. Building on thispolarization sensitivity, several structure such as3×3waveguide arrays, diamond and hexagon patterns are also investigated.2. The waveguide were fabricated in the Er3+-doped aluminum silicate glasswith longitudinal writing configuration and transverse writing configurationrespectively. The different numerical aperture effects on waveguideformation were investigated in detail. The cross-section filamentation withtransverse writing configuration was discussed. The fluorescence spectra andsmall signal gain of waveguide were tested.3. Fabrication of high quality waveguide on active gain medium Yb3+-dopedphosphate glass was realized with the femtosecond laser inscription. The slit widthand focus depth impact on waveguide cross-section were discussed. The differentlaser parameters effects on refractive index change and propagation loss ofwaveguide were investigated in detail, which shows a writing window ofwaveguide formation in Yb3+: doped phosphate glass. Base on a fluorescencespectra test system the fluorescence property of waveguide was test. Usingfinite differences method, the refractive index change was obtained. Stableand continuous wave (CW) laser was achieved in a Fabry–Perot cavityconfiguration by using different reflectivity mirror range from2%to30%output coupler. An output power of23.1mW at a center wavelength of1030nm was obtained. The maximum slope efficient was15%.4. Symmetric embedded waveguides were fabricated in heavy metal oxide glassSF10using slit-shaped infrared femtosecond laser writing in thelow-repetition frequency regime. With the quasi-ps pulse laser, which canthus weaken nonlinear effects that reduce the efficiency and increase energydeposition effectiveness, the typeI waveguide was firstly realized in heavymetal oxide glass. With the cut-back method, the propagation loss of thewaveguide were measured. The impact of the writing parameters on thewaveguide formation in the transverse writing scheme was systemicallystudied. The LP11mode was realized and provide a potential for modeconverter and waveguide sensor. Depressed cladding waveguides wererealized in heavy metal oxide glass ZF13with rotary dual-wedge prism. The property of the material can be maintained with this technique. The efficiencyof waveguide fabrication is higher than traditional depressed claddingtechnique. The single mode and multimode waveguide can be easily achievedvia changing the angle of dual-wedge prism in same matrix.