A band-separated, bidirectional amplifier based on erbium-doped bismuth fiber for long-reach hybrid DWDM-TDM passive optical networks

We propose a band-separated, bidirectional amplifier based on a bismuth-based erbium-doped fiber for use in long-reach hybrid dense wavelength division multiplexing-time division multiplexing passive optical networks (DWDM-TDM-PONs). We also propose a long-reach hybrid DWDM-TDM-PON architecture in which the proposed amplifier can be effectively used. The feasibility of using the proposed amplifier for long-reach hybrid DWDM-TDM-PONs is experimentally investigated by performing a series of signal transmission experiments with an exemplary PON configuration having a total reach of 75 km and 8 split users. Error-free bidirectional signal transmission at a line rate of 10 Gbit/s is successfully demonstrated. A theoretical investigation also shows that the reach/split limitation issue associated with an insufficient WDM signal gain in the experimental demonstration can be easily solved by optimizing the amplifier.