VDSL access system based on rate-adaptive optical sub-carrier multiplexing

The paper proposes an optical access system employing a very high-speed digital subscriber line (VDSL) based on rate-adaptive optical sub-carrier multiplexing (RA-SCM) as a residential gateway for multi-dwelling units in fiber-to-the-building (FTTB). Experiments successfully demonstrate a 20 km transmission of 50 VDSL signals in bidirectional wavelength division multiplexing (WDM) over a single mode fiber as a result of a new method for approximating the spurious levels of an M-ary QAM spectrum that are proportional to constellation size. Calculations examine the trade-off between the maximum transmission distance and the number of subscribers by quantifying the impacts of peak factor fluctuation and chromatic dispersion. Experiments and calculations verify the feasibility and rate-adaptive scalability of the proposed access system based on RA-SCM for first-mile applications in access networks.