Evolution of PMD with the temperature on installed fiber

摘要

Polarization mode dispersion (PMD) is a stochastic, random process because each short discrete length of fiber will have a slightly different core asymmetry, and the extent of the signal degradation caused by PMD is dependent on the state of polarization of light at a given point in the fiber link, and the state of polarization of an optical signal will wander randomly because of temperature changes and mechanical stress. PMD measurements are presented in this work. Data were collected on aerial and buried optical fiber cables mixing paths. DGD data evolution for long term measurements were obtained as prior tasks for fiber characterization where 10-40 Gbit transport system based on DWDM technology will be deployed and PMD effects become significant. DGD long term measurements data have been collected using an EXFO PMD FTB-5500B Analyzer and temperature and wind speed data by the National Institute of Meteorology. Aerial fiber cable-sections will be basically affected by both external agents whose effects must be also prevented before the deployment of DWDM systems that telecommunications operators use at before mentioned transmission rates. In this letter, PMD measurements were obtained from two paths or twin rings, exactly with the same length but over different fibers for each direction resulting on extracted different DGD values. The first path will be represented as clockwise direction and another one as counterclockwise. The analysis will show that the measurements that have been presented at this job agree with those for other accepted references. It will be demonstrated how the time scale of PMD fluctuation here is strongly linked to the rate of temperature change and how the wind speed could modify the final results. Detailed graphs have been analyzed. Also theoretical and real standard deviations have been compared in order to get some conclusions about accuracy in the measurements. This review highlights a lot of trends observed on installed fibers all around the world that are similar to what the authors report here.