Reconfigurable liquid micro-lens system for variable fiber coupling

A system capable of both two-dimensional lateral positioning and focusing of a liquid micro-lens for variable fiber coupling is presented. Lateral positioning and focus adjustment is accomplished by electrowetting-on-dielectrics. The chip is fabricated on a transparent Pyrex substrate and is equipped with a two dimensional array of electrodes featuring a well-defined microstructure which allows accurate positioning of the liquid micro-lens. The system is used as a variable optical fiber coupling element, and measurements of optical power coupled to a fiber as a function of the applied voltage are presented. Applications such as adaptive wave front sensing, optical tweezers, or three- dimensional focus control for microscopy are envisaged.