Study for Instrumentation of Electrooptic Constant and of Photorefractive Sensitivity

研究了高精度电光常数和光折变灵敏度的测量方法，测量了光波导材料的电光常数和光折变灵敏度。在考虑TM0模式传播场分布的情况下，估计了在z切割LiNb03晶体上制作的单模质子交换平板波导层的电光常数。研究了退火对三种类型铌酸锂晶体（未掺杂、钛扩散和掺mgo）质子交换光波导中电光常数r33的影响。精确估计表明，电光常数的退化可以通过退火得到恢复；最好的是未掺杂，其次是钛扩散，最差的是氧化镁掺杂。利用PETi工艺可以制备出简单、易控制的极化无关开关。尽管使用PETi工艺的波导损耗最小，但人们担心，更多的电光效应将被降低，使较小的E-O系数r22无法使用。因此，我们进行了一系列的实验来验证PETi波导在电场作用下的行为与普通Ti波导结构相同。定量测量了质子交换LN和LT波导以及Rb离子交换KTP波导的光折变灵敏度，并估计了它们对波导应用的影响。测量了液相外延生长的LiNb03薄膜波导的光折变灵敏度。在钽酸锂晶体上形成的退火质子交换波导被证明是所有测量样品中最耐光折变效应的，是短波应用的有吸引力的材料。研究了钽酸锂晶体形成的质子交换波导中光折变效应的温度依赖性。实验证明，当样品在高达80ºC的温度下加热时，其抗光折变效应的能力大大提高。少

Instrumentation of the electrooptic constant and photorefractive sensitivity with high precision is investigated and the electrooptic constants and photorefractive sensitivity of optical waveguide materials are measured. Electro-optic constants of single-mode proton-exchanged slab waveguiding layrs fabricated on z-cut LiNb03 crystal are estimated, taking into account the field distribution of the propagating TM0 mode. The effect of annealing on the electrooptic constant r33 in the proton-exchanged optical waveguides on three types of lithium niobate crystals : undoped, titanium-indiffused and MgO-doped, are also investigated. The exact estimation shows that the deterioration of electrooptic constant is recovered by annealing ; the best in undoped, then titanium-indiffused and the worst, MgO-doped. The simple easily controllable polarization independent switches can be fabricated by the PETi process. Although waveguide loss is minimal using the PETi process there is the fear that the el … More ectro-optic effects will be degraded, making the smaller E-O coefficient r22 unusable. Therefore a series of experiments were undertaken to verify that PETi waveguides act in the same was as normal Ti waveguide structures under the influence of the electric field. The photorefractive sensitivity of proton-exchanged LN and LT waveguides and Rb ion exchanged KTP waveguides is quantitatively mesured and their influence on the waveguide applications is estimated. The photorefractive sensitivity of the thin-film LiNb03 waveguides grown by the liquid-phase epitaxy is also measured. The annealed proton-exchanged waveguides formed on the lithium tantalate crystal are proven to be the most resistant to the photorefractive effect in all the measured samples and are attractive materials for short-wavelength applications. Temperature dependence of the photorefractive effect in proton-exchanged waveguides formed on lithium tantalate crystal is investigated. Resistance to the photorefractive effect is proven to be greatly improved when the samples are heated at temperatures as high as 80ﾟC. Less