单模光纤与Ti:LiNbO_3单模平面光波导端面激励耦合的研究

A STUDY OF END-FIRE COUPLING OF SINGLE -MODE FIBER TO Ti : LiNbO_3 SINGLE-MODE PLANAR WAVEGUIDE

本文报导一个单模光纤与单模Ti扩散LiNbO_3光波导的端面耦合及固定连接实验研究.利用电弧烧熔法在单模光纤端面上制成了微透镜,改善了模场匹配程度,采用二维硅V形糟,提高了光纤与波导的对准精度。

Among the most widely investigated devices for Integrated Optics are modulators, switches and spectrum analyzers using Ti-diffused LiNbO3 waveguides. For practical application of such devices the coupling problem of single-mode fibers to single-mode diffused waveguides seems to be one of the most basic and most important problems, To achieve the optimum efficiency in coupling single-mode fibers to single-mode planar waveguides, two conditions must be satisfied: (1 ) the field distribution of their modes must be matched; and ( 2 ) the lateral position between fiber and waveguide must be aligned precisely.An available device with end. fire coupling of single-mode fibers to Ti:LiNbO3 single-mode planar waveguides was designed and fabricated, according to the analysis of coupled mode theory in this paper. To reduce the waist of near-Gaussian beam emitted by fiber, a microlens was formed by arc discharge on the end of single-mode fiber.In this way,the mode distributions of single-mode fiber and single-mode planar waveguide were metched better. In order to achieve precise alignment, two-dimensional silicon V-grooves were used as the positioning alignment frame. The coupling efficiency up to 64% has been measured practically.