PON Monitoring Technologies based on OTDR Techniques: State of the Art and Trends

Passive optical networks (PON) are cost-efficient solutions to deploy a fiber connection in the last mile and they have been massively installed. Therefore, physical layer supervision of these type of networks has become particularly important. So far, the use of an optical time-domain reflectometer (OTDR) is recognized as being the most efficient technique to characterize an optical link. However, the direct application of OTDR in point-to-multipoint networks such as PONs presents severe limitations. Hence, several OTDR-based techniques have been proposed to overcome these limitations. In this paper we present a state of the art of the employed techniques by comparing their performance and feasibility. Finally, we present a novel time-domain reflectometry technique that aims to perform a spectral analysis in PONs by exploiting the frequency-to-time mapping in dispersive media.