A method for manufacturing a fiber taper with a refractive lens, said method comprising the steps of placing a fiber in an axial tension of a given amount; locally heating a portion of the fiber under tension to cause softening and the formation of a constriction in the fiber in the area of heating; removing the tension and continuing the heating to raise the temperature to a point at which the viscosity of the heated material is such that the surface tension causes a further constriction and a transverse separation of the fiber at the constriction; continuing the heating to form the desired curvature of the lens on the separated ends; and then after the desired curvature is formed, stopping the heating to enable the ends to cool and solidify.