2D MEMS electrostatic cantilever waveguide scanner for potential image display application

This paper presents the current status of our micro-fabricated SU-8 2D electrostatic cantilever waveguide scanner. The current design utilizes a monolithically integrated electrostatic push-pull actuator. A 4.0 mu m SU-8 rib waveguide design allows a relatively large core cross section (4 mu m in height and 20 mu m in width) to couple with existing optical fiber and a broad band single mode operation (lambda=0.7 mu m to 1.3 mu m) with minimal transmission loss (85% to 87% output transmission efficiency with Gaussian beam profile input). A 2D scanning motion has been successfully demonstrated with two fundamental resonances found at 202 and 536 Hz in vertical and horizontal directions. A 130 mu m and 19 mu m, corresponding displacement and 0.062 and 0.009 rad field of view were observed at a +/- 150V input. Beam divergence from the waveguide was corrected by a focusing GRIN lens and a 5mm beam diameter is observed at the focal plane. The transmission efficiency is low (similar to 10%) and cantilever is slightly under tensile residual stress due to inherent imperfection in the process and tooling in fabrication. However, 2D light scanning pattern was successfully demonstrated using 1-D push-pull actuation.