飞秒激光在钛蓝宝石晶体中刻写双线型波导的研究  

Study of Ti∶Sapphire Double Line Waveguide Written by Femtosecond Laser

作　　者：刘爽[1,2] 刘欣[1,2] 唐文龙[1,2] 程光华[1] 

机构地区：[1]中国科学院西安光学精密机械研究所瞬态光学与光子技术国家重点实验室,陕西西安710119 [2]中国科学院大学,北京100049

出　　处：《中国激光》2015年第2期66-71,共6页Chinese Journal of Lasers

基　　金：国家自然科学基金(61223007;61378019)

摘　　要：钛蓝宝石晶体作为一种重要的激光介质,具有宽带的吸收光谱及宽带可调谐的发射光谱等特性,使其在集成光学中有广泛的应用前景。这里利用重复频率为1 k Hz,中心波长为800 nm,脉冲宽度为120 fs的飞秒脉冲激光在钛蓝宝石晶体中横向刻写双线型波导,系统地研究了激光写入晶体深度、刻写速度以及波导双线间距对波导导光情况的影响,在写入激光脉冲能量为2μJ,写入深度为175μm,刻写速度为90μm/s,波导双线间距为26μm的条件下,得到一组导光模式较优的双线波导并发现其具有偏振导光现象。利用波导的近场模式强度分布重构了其折射率分布图,得到最大的折射率增加量为1.9×10-4。用散射法测试了光波导的传输损耗为1.82 d B/cm。Ti： sapphire crystal is one of the most important materials as a laser medium, due to its broad absorption band and widely tunable output band, therefore it has wide application in integrated optics. By femtosecond laser with repetition rate of 1 kHz, central wavelength of 800 nm and pulse width of 120 fs, double line waveguide in Ti： sapphire crystal is transversely written. The impacts of the processing conditions, i.e., inscribing depth, writing speed and the track distance on the waveguide formation are systematically studied, and the waveguide with better guiding mode is achieved when laser pulse energy is 2 μJ, inscribing depth is 175 μm, writing speed is 90μm/s and the distance between two tacks is 26μm. And the double line waveguide shows polarization dependent optical guiding. Based on the near-field mode intensity, the refractive index profile of the optical waveguide is reconstructed, and the max positive refractive index change is about 1.9 ×10^- 4. In addition, by using the scattering technique, the propagation loss of the waveguide is 1.82 dB/cm.

关 键 词：集成光学 光波导 飞秒光刻 钛蓝宝石晶体 偏振导光 

分 类 号：TN249[电子电信—物理电子学] TN25