High NA POF Dependence of Bandwidth on Fibre Length

This paper presents experimental and theoretical results that help understand the behaviour of bandwidth in step index plastic optical fibres (SI-POF). The measurements of bandwidth and far field power distribution were analysed using models that relate bandwidth to the fibre exit numerical aperture. To explain the experimental results, it was found necessary to introduce modal interactions into the basic ray theory and, for this, a theoretical approach has been proposed.