UV polymerized microtips on multimode optical fibers

Abstract

The main aim of this paper is to present a geometry shaping of a polymer microtip manufactured on the end of different multi-mode optical fibers by using UV radiation. Used fabrication process is based on a photopolymerization where the microtip grows on one end of the optical fiber when light is launched to its other end. Two different types of the photopolymerizable mixtures and two typical multi-mode optical fibers with different core sizes and refractive index profiles were used for tested microtips. In order to assess their geometries scanning electron microscopy images were used. These images have showed that the influence on the microtip geometry has optical power and spectral characteristics of the UV light. The sensor’s transducer properties were evaluated on the basis of backscatter measurements when a refractive index of a surrounded medium of the microtip changes. Dynamic ranges of tested optical fibers with selected microtips have reached 25-28 dB for the gradient-index multi-mode optical fiber while for the step-index one were around 14 dB. Future research will be focused on increase of dynamic range for the sensor’s application and will be tested as micro-lens.