Considerations on the Use of Digital Signal Processing in Future Optical Access Networks

In this work, we address signal processing techniques targeting increased capacity per wavelength and better receiver sensitivities for next generation optical access networks. We start by recalling the main channel limitations of currently deployed intensity modulated, directly detected passive optical networks. With the intention of providing a benchmarking of signal processing approaches used in communication systems other than optical access, we provide a historic perspective on how digital signal processing emerged in copper access systems and we evaluate powerful techniques envisaged for future mobile generation in both air interface and radio access networks. We then assess signal processing in the light of interoperability by providing insights on burst mode operation and needed protocol and monitoring procedures. Multi-vendor signal processing interoperability between client and central side equipment and with respect to optical transceivers is also considered. Last but not least, we evaluate power consumption due to digital signal processing and forward error correction in disruptive, coherent transmission approaches, which could be very interesting in terms of spectral efficiency and optical power loss budget.