Compensation of fiber dispersion induced-power fading in reconfigurable millimeter-wave optical networks

Abstract

Radio-over-fiber (RoF) systems can be incorporated into a wavelength division multiplexing (WDM) and distributed antenna system (DAS) to vastly increase the data throughput. In this paper, a reconfigurable WDM system at millimeter (mm-wave) frequencies is theoretically proposed and experimentally demonstrated based on an optical frequency comb (OFC) and wavelength selective switch (WSS). The photonic carrier generation using OFC spectra is affected by chromatic dispersion which results in power fading and optical noise. Therefore, the tolerance of the mm-wave heterodyne carrier to fiber propagation is discussed and considered in the proposed architecture. Furthermore, this paper examines how the WSS can pre-compensate the fiber dispersion in terms of power fading on the beating carrier. Experimental measurements show that by variable adjustment of the amount of dispersion compensation applied, power fading of 15 dB can be mitigated and error vector magnitude (EVM) is reduced by 10%. By utilizing the well-known periodic behavior between carrier power penalty and chromatic dispersion, the WSS can also overcome the deep power fading over long fiber lengths (>25 km).