Rayleigh Backscattering Noise Alleviation in Long-Reach Ring-Based WDM Access Communication

In the paper, we propose and design a ring-topology wavelength-division-multiplexing (WDM) access network for long-reach signal transmission. Here, the new central office (CO) and optical network unit (ONU) modules are designed to construct the ring-based architecture for symmetric data connection. Thus, the Rayleigh backscattering (RB) beat noise can be prevented due to the unidirectional downstream and upstream signal connections. In the demonstration, eight WDM wavelengths with 10 Gbit/s on-off keying (OOK) modulation are applied to serve as the symmetric downstream and upstream traffic through 105 km fiber connection without dispersion compensation. In addition, the minimum power budgets of 33.8, 36.1 and 35.4 dB among the eight WDM wavelengths can be obtained at the back-to-back (BtB), 51 and 105 km fiber links, respectively, under the forward error correction (FEC) target.