An Optical Mode Filtering Technique for the Improvement of the Large Core SI-POF Link Performance

In this paper an investigation on the influence of the photodiode's active area and its position relative to the fiber end facet to the performance of a Large Core Step Index Polymer Optical Fiber link is presented. It is shown with extensive numerical simulations that an effective higher order mode filtering occurs, depending on the geometrical properties of the interface, which can significantly improve the performance of the link. These findings are confirmed experimentally. Depending on the photo-receiver's axial offset relative to the fiber facet, an improvement in the BER performance of many orders of magnitude has been achieved for a fiber link of 37.5 m and a bit rate of 1.25 Gbps.