利用缓冲质子源(苯甲酸中掺入一定量的苯甲酸锂)在Z切LiNbO3基底上制作了质子交换平面光波导,得到了不同掺杂摩尔分数(0.5%,1.0%和1.5%)的缓冲质子源质子交换波导的有效扩散系数及折射率分布。随着质子源中苯甲酸锂的摩尔含量逐渐增加,质子交换的有效扩散系数呈指数衰减,同时波导表面折射率增量线性递减。研究了有效折射率的稳定性特征,并与用纯苯甲酸制作的光波导进行了比较,发现利用缓冲质子源制作的LiNbO3光波导的稳定性明显优于纯苯甲酸制作的光波导。

Proton exchange waveguides were fabricated by buffered acid (benzoic acid doped with a certain amount of lithium benzoate) in Z-cut LiNbO3. The effective diffusion coefficients and the index profile were calculated for the waveguides fabricated in buffered benzoic acid with different molar fractions of lithium benzoate with aspect to benzoic acid (0.5%, 1.0% and 1.5%). The effective diffusion coefficient decreases exponentially as the molar fraction of lithium benzoate increases. The surface index increment decreases linearly with the increase of the Li+ mole percent in the proton source. The stabilities of these fabricated waveguides are studied. The results are compared with those from the waveguides fabricated by pure benzoic acid. The stabilities of LiNbO3 proton exchange waveguides can be improved by the exchange with buffered benzoic acid.