EIA: The Effect of Hydrogen on Optical Damage in Ti DiffusedLiNbO3 Waveguides

这项工作是作为工程启动奖(EIA)资助的。研究发现，LiNbO4晶体中氢的存在使钛扩散光波导不易受到光折变光学损伤。这个项目的目的是了解氢的添加如何降低损害。这项工作将分五个阶段进行：(1)在受控气体环境中进行高温退火来平衡(氧、锂和水的活度将同时被控制)；(2)用FTIR、拉曼光谱和光学光谱来分析平衡后的晶体；(3)通过写入全息衍射栅来测量体光折变效应；(4)用钛的内扩散制成平面光波导；以及(5)将测量光波导中的光学损伤。每个步骤的结果将相互关联，以了解氢缺陷的存在及其影响。更好地了解铌酸锂中的氢将有助于制造寿命更长、功率传输能力更高的光波导。这项建议描述了将进一步表征铌酸锂的光折变效应的工作。在拟议的研究中获得的理解应该允许制造改进的光学设备。这项研究的主要目的将是确定可能存在于铌酸锂中的与氢有关的缺陷，并评估它们对光折变效应的积极或消极影响。将通过研究在严格控制的环境中平衡的晶体来进行鉴定。

This work is funded as an Engineering Initiation Award (EIA). The presence of hydrogen in lithium niobate crystals has been found to make Ti-diffused waveguides less susceptible to photorefractive optical damage. This project is aimed at understanding how the hydrogen additions lower damage. The work will proceed in five stages: (1) Annealing at high temperature in a controlled gas environment will be used for equilibration (oxygen, lithium, and water activities will be controlled simultaneously); (2) FTIR, Raman, and optical spectroscopies will be used to analyze the equilibrated crystals; (3) the bulk photorefractive effect will be measured by writing holographic diffraction gratings; (4) planar waveguides will be made by in-diffusion of titanium; and (5) optical damage in the waveguides will be measured. The results of each of these steps will be correlated to understand what hydrogen defects are present and what their effects are. A better understanding of hydrogen in lithium niobate will allow fabrication of waveguides with longer life and higher power transmission capabilities. This proposal describes work which will further characterize the photorefractive effect in lithium niobate. The understanding obtained in the proposed study should allow the fabrication of improved optical devices. The major thrusts of this study will be to identify hydrogen related defects which are likely to be present in lithium niobate, and to assess their positive or negative effects on the photorefractive effect. The identifications will be made by studying crystals which have been equilibrated in carefully controlled environments.