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DSP-based optical access approaches for enhancing NG-PON2 systems

Motivated by recent progress in next-generation PON2, or NG-PON2, standardization, this article reviews digital signal processing technologies to further enhance NG-PON2 systems by realizing flexible and cost-effective optical access network deployments. First, flexible speed upgrades by DSP-enabled advanced modulation and multiplexing approaches are described, followed by a consideration of cost-performance trade-offs. Next, reach extension using DSP-based digital coherent reception and impairment compensation is overviewed. Finally, as a future goal, access network virtualization with reconfigurable optical line terminals and optical network units is discussed.