Title :
Microlens fabrication by selective oxidation of composition-graded digital alloy AlGaAs
Author :
Ki Soo Chang ; Young Min Song ; Yong Tak Lee
Author_Institution :
Dept. of Inf. & Commun., Gwangju Inst. of Sci. & Technol., South Korea
Abstract :
We have fabricated refractive microlenses using selective oxidation of composition-graded digital alloy AlGaAs. The chirped short period superlattice of GaAs-AlAs was used to grade the composition of AlGaAs along the growth direction for a reproducible and controllable composition and oxidation profile. The oxidized profile of linearly composition-graded digital alloy AlGaAs shows a circular convex lens shape. The focused spot pattern of the beam at the focal point of the fabricated circular buried microlens reveals the strong focusing function of the microlens. Circular buried microlenses with mesa diameter of 20 μm exhibited focal length of 28-33 μm and a focused spot diameter of 4.0-6.4μm, which are varied by oxidation time.
Keywords :
III-V semiconductors; aluminium compounds; gallium arsenide; integrated optics; light refraction; microlenses; optical fabrication; optical focusing; oxidation; semiconductor devices; 20 mum; 4.0 to 6.4 mum; AlGaAs; AlGaAs composition; chirped superlattice; circular buried microlens; circular convex lens shape; composition-graded digital alloy; focal point; focused spot beam pattern; microlens fabrication; oxidation profile; refractive microlenses; selective oxidation; short period superlattice; strong focusing function; Digital alloys; Fabrication; Lenses; Microoptics; Optical arrays; Optical devices; Optical refraction; Optical superlattices; Oxidation; Vertical cavity surface emitting lasers; AlGaAs; digital alloy; microlens; selective oxidation;
Journal_Title :
Photonics Technology Letters, IEEE
DOI :
10.1109/LPT.2005.860051
