Lan Hsiao-Chin, Hsiao Hsu-Liang, Chang Chia-Chi, Hsu Chih-Hung, Wang Chih-Ming, Wu Mount-Learn
Department of Optics and Photonics, National Central University, Jhong-li, 32001, Taiwan.
Opt Express. 2009 Nov 9;17(23):20938-44. doi: 10.1364/OE.17.020938.
A monolithically integrated micro-optical element consisting of a diffractive optical element (DOE) and a silicon-based 45 degrees micro-reflector is experimentally demonstrated to facilitate the optical alignment of non-coplanar fiber-to-fiber coupling. The slanted 45 degrees reflector with a depth of 216 microm is fabricated on a (100) silicon wafer by anisotropic wet etching. The DOE with a diameter of 174.2 microm and a focal length of 150 microm is formed by means of dry etching. Such a compact device is suitable for the optical micro-system to deflect the incident light by 90 degrees and to focus it on the image plane simultaneously. The measured light pattern with a spot size of 15 microm has a good agreement with the simulated result of the elliptic-symmetry DOE with an off-axis design for eliminating the strongly astigmatic aberration. The coupling efficiency is enhanced over 10-folds of the case without a DOE on the 45 degrees micro-reflector. This device would facilitate the optical alignment of non-coplanar light coupling and further miniaturize the volume of microsystem.
实验证明了一种由衍射光学元件（DOE）和硅基45度微反射镜组成的单片集成微光学元件，可促进非共面光纤到光纤耦合的光学对准。通过各向异性湿法蚀刻在（100）硅片上制造深度为216微米的倾斜45度反射镜。通过干法蚀刻形成直径为174.2微米、焦距为150微米的DOE。这种紧凑的器件适用于光学微系统，可将入射光偏转90度并同时将其聚焦在像平面上。测量得到的光斑尺寸为15微米的光图案与具有离轴设计以消除强像散像差的椭圆对称DOE的模拟结果吻合良好。与45度微反射镜上没有DOE的情况相比，耦合效率提高了10倍以上。该器件将有助于非共面光耦合的光学对准，并进一步使微系统的体积小型化。
