[OPTICAL REVIEW Vol. 8, No. 5 (2001) 373-377]
Batch Assembly Micro-Ball Lens Array for Si-Based Optical Coupling Platform in Free Space
Sheng-Chih SHEN1,*, Cheng-Tang PAN3,**, Hwai-Pwu CHOU1 and Min-Chieh CHOU2
1Department of Engineering and System Science, 2Department of Materials Science and Engineering, Tsing Hua University, Hisnchu 101, Section 2, Kuang Fu Road Hsinchu, Taiwan, 3Industrial Technology Research Institute, MIRL/ITRI Bldg. 22, M400, 195-3 Chung Hsing Rd., Section 4, Chutung, Hsinchu, Taiwan
(Received April 13, 2001; Accepted May 30, 2001)
The paper presents novel concepts of batch fabrication of micro-ball lens array technology integrated on the silicon-based wafer which can improve the appropriate distance for optical fiber coupling. The silicon-based optical coupling platform consists of a self-parking framework (including flat-topped mesa and intersection of two v-grooves) and micro-ball lens array for optical fiber coupling purposes. The structure of optical coupling platform is able to improve the distance between fiber and micro-ball lens and to increase coupling efficiency. Optical measurement reveals an insertion loss below 2.5 dB with wavelength 635 nm in single-mode fiber. The micro-ball lens array is batch fabricated by polymeric material and thick photoresist, and then bonded onto a flat-topped mesa that adjoins to the v-groove. The corner compensation offers a method to fabricate the flat-topped mesa in the intersection of two v-grooves. This fabrication process not only provides accurate coupling distance between fibers and micro-ball lens, but also reduces micro-assembly cost.
Key words : optical coupling platform, micro-ball lens, v-groove, wafer bonding, anisotropic etching