采用稀释硬脂酸和高温质子交换技术,研究了单偏振α相铌酸锂光波导的制备工艺。开发了一种高温密闭装置,通过提高蒸汽压的方法实现了350 ℃质子交换。波导折射率分布测试采用了棱镜薄膜耦合m线技术结合统计迭代法拟合的方法,晶相分析采用了红外吸收光谱技术。实验结果表明,掺入1.1%硬脂酸锂质量比例的硬脂酸作为缓冲质子源,经350 ℃/6 h高温质子交换,可以形成α相铌酸锂光波导,稀释度为1.3%时,同样的温度/时间条件下,可以获得632.8 nm单模α相铌酸锂光波导。

The preparation process of single polarization α-phase LiNbO3 optical waveguide is studied using dilution of stearic acid and high temperature proton exchange technology. A high temperature sealing device is developed. A method by increasing vapor pressure to achieve the 350 ℃ proton exchange is proposed. Waveguide refractive index distribution is tested by using prism film coupling m-line technology and the statistical iterative method fitting. Crystal phase is analyzed by testing infrared absorption spectrum technique. The experimental results show that α-phase LiNbO3 optical waveguide can be produced under the conditions of the stearic acid doped with 1.1% lithium stearate mass proportion as buffer proton source and 350 ℃/6 h high temperature proton exchange. Single mode α-phase LiNbO3 optical waveguide at 632.8 nm wavelength can be produced under the conditions of the same temperature, time and the dilution of 1.3%.