Wiener filter equalization for higher data rate over 100m large-core 1mm SI-POF

Abstract

Increasing data rate has been the demand of communication systems all along. While Glass Optical Fibre (GOF) has established itself as the backbone, Plastic Optical Fibre (POF) is a strong candidate for the - short haul - last mile communication. It has all the advantages of Glass Optical Fibre (GOF) except that its high attenuation and multimodal dispersion restrict its bandwidth and reach severely. The low cost of POF technology and its ease of use, make it apt for further investigating - how to enhance data rate, in short haul POF links. Harnessing the spectral efficiency, of multilevel modulations (M-PAM) would be an obvious choice but with that comes the problem of noise becoming significant, as the distance, between modulated signal levels, decreases. At this point, DSP (Digital Signal Processing), in terms of equalization, becomes relevant. This paper theoretically proposes - how data rate, in short haul low cost link, using a step index Poly Methyl-methacrylate Plastic Optic Fiber (PMMA SI-POF), can be increased, using equalization. Hitherto, all experimental efforts trying to achieve gigabit data rate have used DFE (Decision Feedback Equalizer). This paper suggests how a Wiener filter can be used as an equalizer and the signal can be equalized using only FFE (Feed Forward Equalizer) with fewer taps. The theoretical modeling of the fiber, the channel passing of a PRBS (Pseudo Random Bit Sequence) test signal and the equalization are done in Matlab. Limited experimental validation is done by recovering, fiber passed signals, using the equalizer model, offline. Finally, it is sought to establish that given their low cost and popularity there is a strong case for adopting POF in FTTH (fiber-to-the-home) and Ethernet space. With this objective - this paper puts forth the concept of leveraging POF's extra bandwidth, over the Gaussian fit, to push 1.6 Gb/s data rate in POF - over a distance of 100m - using 16-PAM modulation and effective Wiener filter equalization.