An experimental assessment of the BSOFDM-PON architecture

In this paper, we present experimental investigations of a 6 Gbps passive optical networks (PON) based on bandwidth scalable orthogonal frequency division multiplexing (BSOFDM-PON). The BSOFDM-PON architecture is composed by an optical line terminal (OLT) and three optical network units (ONUs) located at distances ranging from 25 to 65 km of standard single-mode fibers (SSMF). The influence of the frequency guard band designed to accommodate intermodulation distortions (IMD) inherit of direct-detection optical OFDM (DDO-OFDM) systems is experimentally evaluated. Our results show that this guard band strongly depends on the received optical power (fiber length) and the subcarrier modulation format. An error free transmission in 65 km of SSMF for a scalable bandwidth of 3 GHz occupying 4096 subcarriers mapped in 4QAM is achieved without the frequency gap of the guard band.