Mechanism of refractive index increase in silica glass for the development of fiber-optic photodevices

用于开发光纤光电器件的石英玻璃折射率增加机制

基本信息

批准号：
12450132
负责人：
OHKI Yoshimichi
金额：
$ 6.91万
依托单位：
Waseda University
依托单位国家：
日本
项目类别：
Grant-in-Aid for Scientific Research (B)
财政年份：
2000
资助国家：
日本
起止时间：
2000 至 2002
项目状态：
已结题

项目摘要

The refractive index change induced in a transparent material by UV photon or ion irradiation promises direct drawing of a waveguide that can be used as optical gratings. Structural changes in silica glass induced by ion microbeam were evaluated using microscopic photoluminescence and Raman scattering, and optical and atomic force microscopes (AFM) measurements. The AFM measurements on the microbeam irradiated area show the formation of a groove on the surface. In addtion, a cross sectional observation on the surface parallel to the incident plane reveals surface deformation along the ion tracks, which is deepest at the projected range of ions. Taking into account the possible structural changes of silica induced by energy deposition, the measured topological changes at the front and side surfaces result from internal compaction of silica glass. Refractive index changes were estimated from the Lorentz-Lorenz relationship using the distribution of the internal compaction estimated by the AFM measurements. A small refractive index change was observed along the ion tracks besides a much stronger index change at the projected range, suggesting that energy depositions by the ionization as well as by the atomic collision should be taken into account.It has also become clear that the refractive index change can be induced by UV photons from a KrF excimer laser in a-SiO_x N_y : H films prepared by PECVD. Fabrication of a diffraction grating was performed using a phase mask made of a high quality fused silica plate. The surface of the fabricated grating observed by scanning electron microscopy (SEM). A clear square-toothed pattern with periodicity of around 1 μm can be observed. Furthermore, from the Fraunhofer diffraction pattern, the periodicity of the grating pattern was estimated to be around 1 μm, which agrees with the SEM image. This simply demonstrates that a-SiO_xN_y : H can be processed by UV photon irradiation.

紫外光子或离子辐照在透明材料中引起的折射率变化有望直接绘制波导，可用作光栅。使用显微镜光胶片和拉曼散射以及光学和原子力显微镜（AFM）测量评估了由离子微束诱导的二氧化硅玻璃的结构变化。微束辐照区域上的AFM测量表明，表面凹槽的形成。此外，在与入射平面平行的表面上进行的横截面观察显示，沿离子轨道的表面变形在离子的预计范围最深。考虑到能量沉积引起的二氧化硅的可能结构变化，二氧化硅玻璃的内部压实导致了前面和侧面的拓扑变化。使用AFM测量值估计的内部压实分布从Lorentz-Lorenz的关系估算了折射率变化。除了在预计范围内的指数变化更大，沿离子轨道的折射率变化很小，这表明应考虑电离以及原子碰撞的能量沉积。还应考虑到折射指数的变化可以通过krf excimer excimer excimer laser laseer in a-sio__________ hy的uv Photos诱导折射指数的变化。使用由高质量融合二氧化硅板制成的相掩膜进行衍射光栅的制造。通过扫描电子显微镜（SEM）观察到的制成光栅表面。可以观察到透明的平方齿图，周期性约为1μm。此外，从Fraunhofer衍射模式来看，光栅模式的周期性估计约为1μm，与SEM图像一致。这只是证明了a-sio_xn_y：h可以通过紫外光照射处理。