Title :
Retroreflecting optical modulator using an MEMS deformable micromirror array
Author :
Chan, Trevor K. ; Ford, Joseph E.
Author_Institution :
Dept. of Electr. & Comput. Eng., Univ. of California, San Diego, CA, USA
Abstract :
A modulating corner-cube reflector with one microelectromechanical-system (MEMS) mirror that deforms from a flat into a hexagonal array of concave reflective microlenses to disperse the retroreflected wavefront is demonstrated. It is shown that such retromodulators can operate under a wide range of wavelength and angle illumination using Huygens-Fresnel propagation analysis, and this analysis is verified using devices fabricated by surface micromachining. A gold-coated silicon-nitride membrane suspended over 1-mm-diameter circular cavities had a resonant frequency of 160 kHz and 0.55-μm maximum deformation with 79 V applied. While this deflection was only 2/3 of the design value of 0.8 μm, we measured an up to 7:1 modulation contrast ratio from a prototype retromodulator, which achieved 100-kHz modulation over a 100-nm optical bandwidth, a 35° range of incident angles, and temperatures ranging from 20 to 100°C.
Keywords :
micromachining; micromechanical devices; micromirrors; optical arrays; optical communication equipment; optical fabrication; optical modulation; 1 mm; 100 kHz; 160 kHz; 20 to 100 degC; 79 V; Huygens-Fresnel propagation analysis; MEMS; deformable micromirror array; gold-coated silicon-nitride membrane; microlenses; modulation contrast ratio; retroreflecting optical modulator; surface micromachining; Lenses; Lighting; Micromechanical devices; Micromirrors; Microoptics; Mirrors; Optical arrays; Optical modulation; Optical surface waves; Surface waves; Microelectromechanical devices; modulation; optical communication; optical diffraction; remote sensing;
Journal_Title :
Lightwave Technology, Journal of
DOI :
10.1109/JLT.2005.859853
