利用重复频率为25 MHz的飞秒激光刻写铌酸锂掩埋式光波导,研究了在激光作用中心及热影响区域的物质结构,采用650 nm的激光进行端面耦合实验,观测刻写区域波导的光传输特性及损耗测量。研究发现,在激光刻写区域的上下两个部位分别形成了传输损耗低于1.5 d B/cm的单模光波导,而刻写区域中心未形成波导结构且光传输性能较弱。拉曼分析显示,刻写区域上下两个部位形成了致密化波导结构,而刻写中心形成了大尺度的缺陷。 Lithium niobate embedded optical waveguide was written by using femtosecond laser repetition rate of 25 MHz to study the material structure in the laser center and the heat affected zone. The 650 nm laser was used for the end-face coupling experiment to observe the optical transmission Characteristics and loss measurement. It is found that single mode optical waveguides with transmission loss less than 1.5 d B / cm are formed at the upper and lower parts of the laser scribe region, respectively. However, the waveguide structure is not formed at the center of the scribe region and the optical transmission performance is weak. Raman analysis shows that the densified waveguide structure is formed in the upper and lower parts of the writing area, and the large scale defects are formed in the writing center.