Bulb-ended fibre coupling to LED sources

摘要

An optical fibre with a spherical-bulb end is shown to be an efficient lens structure for coupling light from a small Lambertian source into the fibre. The coupling efficiency is calculated by determining the irradiance distribution of light accepted by the fibre after passage through the bulb end. The theoretical calculations are verified using an experimental technique that simulates the coupling geometry. The experimental technique is a simple method that can be readily extended to the evaluation of more complex fibre-coupling configurations.