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

TLDR

The study proposes and demonstrates a WDM‑based point‑to‑multipoint RF dissemination scheme for tree‑topology fiber networks and investigates its long‑term performance limits imposed by temperature‑induced group‑velocity dispersion. By passively canceling link‑induced phase fluctuations at the remote end, the authors implement the scheme over 38.5 km and 50 km links, achieving 1 GHz signal instability of ~10⁻¹⁷ after 10⁴ s and validating the design with 17.4 nm wavelength spacing. Experiments under a 21 °C temperature swing show overlapping Allan deviation matching simulations after 10⁴ s, confirming the theory and demonstrating its utility for predicting and optimizing WDM‑based RF dissemination capacity.

Abstract

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.