Variable optical attenuator using planar light attenuation scheme based on rotational and translational misalignment

Abstract

In the last decade, extensive developments of microelectromechanical systems based thermal actuator and/or electrothermal actuators have been dedicated to the applications, such as data storage devices, relays and optical switches, etc. In this paper, we demonstrated a novel planar micromechanism comprising a tilted mirror driven by a V-beam electrothermal actuator via a link beam. This electrothermally driven tilted mirror can have static displacement with a motion trace including rotational and translational movement. The rotational and translational misalignment of reflected light spot toward the core of output port fiber will lead to light attenuation. In other words, the attenuation is controlled in terms of the position of tilted mirror depending on driving dc voltage. This new micromechanism has granted us a more efficient way to perform the light attenuation regarding to the other kinds of planar variable optical attenuators. These devices were fabricated by the deep reactive ion etching process and can reach 30-dB attenuation at 7.5 V driving voltage. The polarization dependant loss is less than 0.1 dB within the 30-dB attenuation region. The static and transient characteristics of devices operated at ambient room temperature environment show good repeatability and stability.