Monolithic integration of elliptic-symmetry diffractive optical element on silicon-based 45 degrees micro-reflector.
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.
Lan
Hsiao-Chin
HC
Department of Optics and Photonics, National Central University, Jhong-li, 32001, Taiwan.
Hsiao
Hsu-Liang
HL
Chang
Chia-Chi
CC
Hsu
Chih-Hung
CH
Wang
Chih-Ming
CM
Wu
Mount-Learn
ML
D004867:Equipment Design; D007909:Lenses; D008027:Light; D055096:Optical Devices; D055095:Optics and Photonics; D010825:Physics / Q000379:methods; D012031:Refractometry / Q000295:instrumentation; D012825:Silicon
D012825:Silicon