Electrothermal actuation provides the long displacement required by an increasing number ofMEMS applications. However, its high power consumption is a limiting factor, especially for applications in which multiple actuators are required. An iris type variable optical attenuator (VOA),5 which was recently introduced by our group, is an example of such an application. In this paper we introduce an improved single sided electrothermal design, which
reduces the power consumption by a factor of 70%, while at the same time removing an undesired mechanical resonance. The optical performance is also improved by the introduction of a novel aperture shape which provides higher extinction, independent of the process technology.