WDM-based radio frequency dissemination in a tree-topology fiber optic network

In this paper, we propose and demonstrate a scheme to achieve point-to-multipoint dissemination of radio frequency (RF) signals in a local area fiber optic network with tree topology based on wavelength-division multiplexing (WDM) technique. The phase changes caused by the fluctuations of the transfer links are passively canceled at remote end instead of at local end, which makes it feasible to flexibly build a tree-topology local area dissemination network with great cost-effectiveness. For the first time, we study the limit of long-term performance which is caused by temperature-induced variation of group velocity dispersion (TIVGVD) in dissemination networks using WDM techniques. In the proof-of-concept experiments, 38.5 km and 50 km fiber links are established to disseminate a 1 GHz frequency signal with fractional instability of 10(-17) order after 10(4) s averaging time. Then 17.4 nm wavelength spacing is introduced between local carrier and user carrier to verify the theoretical analysis. Under a controlled fiber temperature variation of about 21 °C, the obtained overlapping Allan deviation (ADEV) agrees well with the simulation results after 10(4) s time scales, which proves the validity of our theory. The theory has practical values in predicting and optimizing the capacity and performance of a WDM-based local area RF dissemination network.