Biquad filter based equalization for PMMA SI-POF links

Abstract

This paper proposes the use of an analog biquad filter as an equalizer for PMMA based step index plastic optical fiber (POF) links. We show both theoretically and experimentally that this approach achieves 100 Mbit/s over for 100 m of fiber. The material properties of the POF channel causes significant intersymbol interference SNR degradation for long link lengths. The use of DSP based equalization, while effective, imposes significant additional complexity. We propose the design and implementation of an analog biquad filter that is tuned using fiber modeling to effectively compensate the dispersive limitations. We show experimentally that the designed filter is able to successfully overcome the dispersion limits over a large range of fiber lengths and data rates.