Polymer microoptoelectromechanical systems: Accelerometers and variable optical attenuators

This paper presents the design, fabrication and characterization of polymer microoptoelectromechanical systems (MOEMS). An optical accelerometer and a variable optical attenuator (VOA) based on SU-8 are presented. Both devices consist on a quad-beam polymer structure and can be fabricated with a simple technology, requiring only two photolithographic steps. Self-alignment structures for fast and accurate fiber optic positioning have also been implemented in both devices. The accelerometer working principle consists on a misalignment between the three waveguides, which comprise the structure, as acceleration is applied. Experimental optical sensitivities of 13.1 dB/g for negative and 17.5 dB/g for positive accelerations, and a high repeatability in an uncontrolled atmosphere are observed. Using the same devices and taking advantage of the high thermal expansion (CTE) of the SU-8, it is possible to obtain a low-power consumption VOA. Experimental results show an attenuation of 20 dB for a power consumption of 12 mW.