Investigation of PMD in old optical fibres and cables and PMD effects on network upgrades to higher bit rates

PMD (polarization mode dispersion) is a significant effect in high data rate optical systems. When telecommunication operators want to upgrade their network with higher bit rate systems, PMD may be a key limitation. As laying new fibres for this purpose is costly, time consuming and preferably avoided, testing and qualification of existing fibres, often 10-15 years old, becomes very important. NIT (National Institute of Telecommunications) is actively working on the analysis of PMD effects in digital networks and experimental verification of performance of various optical fibres and cables used in Poland.