INSTITUTE OF PHYSICS PUBLISHING
JOURNAL OF MICROMECHANICS AND MICROENGINEERING
J. Micromech. Microeng. 13 (2003) 400–411
PII: S0960-1317(03)54050-5
Optical and mechanical models for a variable optical attenuator using a micromirror drawbridge A Q Liu1, X M Zhang1, C Lu1, F Wang2, C Lu2 and Z S Liu2 1 School of Electrical and Electronic Engineering, Nanyang Technological University, Nanyang Avenue, Singapore 639798 2 Division of Computer Aided Engineering, Institute of High Performance Computing, 89C Science Park Drive, #02-11/12 Rutherford, Science Park 1, Singapore 118261
E-mail:
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Received 27 September 2002, in final form 24 February 2003 Published 18 March 2003 Online at stacks.iop.org/JMM/13/400 Abstract In this paper, we develop optical and mechanical models of a surface micromachined variable optical attenuator (VOA) having an initial tilt angle. The proposed models are employed to compare various characteristics of the VOA such as snap-down voltage, attenuation versus driving voltage, and the rise time and the fall time based on the experimental data. In addition, the analytical models of the static and dynamic behavior of the drawbridge are verified using the results from the finite element method. We obtain reasonable accuracy between the results from the experiment and the proposed models.
1. Introduction Variable optical attenuators (VOAs) have been widely used in dense wavelength division multiplexing (DWDM) systems to equalize the power levels of multiple wavelength channels and to obtain flat gain of optical amplifiers [1]. Specifications such as low insertion loss (30 dB), high response speed (100 nm) and small polarization dependence loss (50 dB) and fine resolution (0.1 dB), but their low speed (∼0.5 s), bulky size and high cost limit the applications. Microelectromechanical systems (MEMS) technology has been found to be a promising approach for VOAs due to the advantages of small size (
