Fabrication of Microlenses and Optical Waveguides by Laser-induced Deposition.

Abstract

Three-dimensional dielectric microlenses and ridge-type optical waveguides were fabricated by laser-induced thin film depositiontechniques. For this purpose films were produced not only in localized areas on substrates, but also with film thickness profile controlled as suitable for each device. A spherical thickness distribution was obtained in the central part of silicon oxide films deposited by CO2-laser chemical vapor deposition (CVD), while the shape was improved by post-deposition wet etching. Dielectric optical waveguides were produced also from ridges drawn by laser CVD, where the CO2 laser and an argon-ion laser were used for quartz and silicon substrates, respectively. Laser-induced vaporization provided a point molecular source, and by placing a mask between a quartz target and a substrate either microlenses or optical waveguides were produced with the thickness profile controlled by residual gas pressure in a cell. Finally, we used an ArF laser to modify etch rates of silicon nitride films locally during plasma deposition and produce optical waveguides.