Monitoring à long terme d'une liaison optique aérienne cohérente à 40 Gbit/s

Abstract

The development of polarization multiplexed modulation formats have generated renewed interest in the study of polarization effects in coherent optical links, which could result in system failures. The study of these polarization effects could be used to design the digital signal processing (DSP) modules, which are used in the coherent transponders, and whose function is especially to compensate for polarization effects such as polarization mode dispersion (PMD). This thesis presents the analysis of the performance parameters measurements and the polarization activity performed on a 40-Gb/s coherent optical link mainly deployed on an optical ground wire fiber (OPGW). The measurements were made by means of a coherent transponder dual polarized, modulated with dual-polarization quadrature phase-shift keying (DP-QPSK) and a polarimeter for over two years. The first part presents the study of the temporal evolution of the different parameters characterizing the transmission system, such as the bit error rate (BER), the differential group delay (DGD) or the polarization mode dispersion (PMD). These parameters were measured by a 40-Gb/s coherent transponder DP-QPSK, with a sampling rate of 1 kHz for several seasons in order to determine the characteristics of the link and then analyzed through processing tools developed under Matlab®. The second part presents the analysis of fast polarization changes using an Agilent N7786B polarimeter. Stokes parameters were measured with a sampling rate of 20 kHz for 182 days over a period of 22 months. The angular rotation rate of the Stokes vector was calculated for all the measurements and the study of fast polarization changes was performed on all the measurements using a tool developed in Matlab. The harmonic analysis of polarization states was performed and, finally, a study of the polarimeter noise was proposed through a simulation tool developed in Matlab.

Date	30 Oct 2015
Original language	French
Awarding Institution	École de technologie supérieure
Supervisor	Christine Tremblay (Supervisor)