Monte Carlo simulation for fiber hemispherical micro-lenses

The Monte Carlo model for a fiber hemispherical micro-lens is proposed. A hybrid method that uses both geometrical ray tracing and wave optics simulation is introduced for building the model of a fiber hemispherical micro-lens. The advantages of this method are that it can be taken into account the non-paraxial effects such as aberrations and diffraction effects. The properties of tapered-cladding single-mode fiber hemispherical micro-lenses are investigated by Monte Carlo simulation. And the simulation results show the waist and the maximum axial intensity are not located at the geometrical focal plane of the micro-lens, and their positions are not coincident with each other. And when the curvature radius of the fiber micro-lens is lager than 2 times of the fiber mode radius, the contribution of the spherical aberration on the spot size can be ignored.