Experimental distribution of OFDM-UWB radio signals along directly modulated long-reach PONs indicated for sparse geographical areas

The distribution of three orthogonal frequency division multiplexing (OFDM) ultra wideband (UWB) bands along directly modulated long-reach (LR) passive optical networks (PONs) is demonstrated experimentally. Adequate selection of the UWB signal applied to the directly modulated laser (DML) and fixed in-line optical dispersion compensation are shown as effective solutions to reach 130 km of standard single-mode fibre. In addition, error vector magnitude (EVM) levels compliant with the UWB standard are achieved for LR-PONs with reaches between 75 km and 130 km. It is also shown that, for optical channel spacing as narrow as 0.2 nm, the proposed system suffers from negligible linear inter-channel crosstalk as the EVM of the UWB bands transmitted in the central channel of a wavelength division multiplexing (WDM) signal consisting in three optical channels, is similar to the EVM of the UWB bands transmitted in that channel when single-channel operation is considered. These results demonstrate that the proposed directly modulated LR-PON is an adequate solution to deliver the UWB signals to users' premises located in sparse take-up geographies.