考虑到离子交换和离子扩散工艺的特殊要求, 设计并熔制了适合于离子交换工艺的硅酸盐玻璃材料SiO2-B2O3-Al2O3-R’O-R2O(R’=Ca, Mg; R=Na, K). 采用Ag+/Na+熔盐离子交换和电场辅助离子扩散工艺在这种玻璃材料基片上获得了掩埋式条形光波导. 光学显微镜和电子探针分析表明高折射率的Ag+扩散区位于玻璃基片表面以下约10μm处, 形成光波导的芯部. 光波导芯部尺寸约为8μm×8μm, 与单模光纤芯径尺寸相当, 保证了较低的光纤耦合损耗. 对光波导的测量结果得出:在波长为1.5μm处条形光波导的传输损耗约为0.1dB/cm, 与单模光纤的耦合损耗约为0.2~0.3dB. 条形光波导的传输损耗与材料本身的损耗接近, 表现出掩埋式光波导的低损耗特征. 分析表明, 经过进一步优化, 这种光波导制备技术可用于低损耗光波导器件的制作.
Silicate glass of system SiO2-B2O3-Al2O3-R’O-R2O(R’=Ca, Mg; R=Na, K)was designed and melted for ion-exchanged integrated optical waveguide chip, on consideration of the suitability of ion-exchange and ion-diffusion process on this glass substrate, buried channel waveguide was manufactured by Ag+/Na+ ion-exchange in mixed melted salts, and subsequently field-assisted ion-diffusion process. Observation of optical microscope and electron microprobe show that Ag+ diffusion zone is driven to approximately 10μm under the glass substrate surface. The Ag+ diffusion zone possesses higher refractive index than glass substrate, and thus acts as the waveguide core. This waveguide core is typically in dimension of 8μm×8μm, matching well with that of single-mode-fiber core, which ensures a low coupling loss. Propagation loss and coupling loss with single-mode-fiber is measured to be 0.1dB/cm and 0.2-0.3dB/facet respectively, at the wavelength of 1.55μm. The propagation loss is very close to glass material inhere loss at the same wavelength, a typical characteristics of buried waveguide. It shows that the waveguide manufacturing process is promising for implementation of low-loss integrated optical devices.