Tailoring the geometry of polymer tips on the end of optical fibers via control of physico-chemical parameters

This paper deals with the improvement of polymer microlenses at the extremity of an optical fiber. The process reported previously involves a spatially controlled light-induced polymerization within a drop of liquid photopolymerizable formulation deposited on the end of a cleaved fiber. The process is of highest interest for applications in optical connecting and optical fiber sensor since it is fast, highly flexible (curvature radii ranges from 0.2 to 200 mu m) and does not require expensive equipment. In particular, the spatial extend of the photopolymerization was demonstrated to be highly dependent on physico-chemical parameters of the formulation. The influence of parameters that govern the photopolymerization reaction and light propagation in the photopolymerizable medium such as irradiation time, light power, oxygen quenching and dye absorption, were studied in order to control the final properties of the polymer tip. The present study allowed selecting the synthesis parameters leading to well-controlled geometrical structures. From a fundamental point of view, this study appeared to be an interesting means to investigate the photostructuration of polymers at the micro- and nanoscales. (C) 2008 Elsevier B.V. All rights reserved.