Radiation characteristics of a tapered cylindrical optical fiber

Abstract

Output coupling of light from a conically tapered optical fiber is investigated. Such a technique may be used to provide “wide-angle” illumination from a single fiber of low numerical aperture. Experimental results for a series of fibers of varying taper angles are presented. It is found experimentally that light which is coupled out of a taper is widely dispersed when the taper angle is large. Based upon modified geometrical optics we present a theory which qualitatively predicts the experimentally measured radiation intensity patterns.