Deterioration of taper lens performance due to taper asymmetry

Abstract
The influence of rotationally asymmetrical, i.e. bent drawn, fiber tapers on the coupling performance of taper lenses used for laser diode- or LED-to-single-mode-fiber coupling is investigated. It is found by experiments that the lateral offset of the taper tip with respect to the fiber axis should be below approximately=6 mu m if a significant increase in coupling loss is to be avoided. The experimental results are interpreted by numerical simulations applying the beam propagation method.