Thermomechanically Driven Polymer Actuator for High-Precision Optical Alignment

Precise thermomechanical positioning has been demonstrated in an actuator device based on a silicone elastomer with a high thermal expansion coefficient. The actuator performance has been characterized using optical microscopy, and the actuator has been deployed in an optical coupling experiment to demonstrate the precise positioning of a ball lens between two single-mode fibers. Tuning of the coupling efficiency has been achieved in excellent agreement with calculated values and precise positioning (better than 200 nm) over a range of 20 mum has been achieved with low power dissipation and temperature control of plusmn0.2 degC. The actuation is linear with temperature over the entire range of motion. This linearity was achieved while amplifying the thermally induced expansion of the elastomer along the alignment axis by a factor of 2.1 over its nominal isotropic expansion value by physically constraining the material in the device. The device performance gives favorable implications for the use of such actuators in optical packaging applications