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