Chromatic and polarization mode dispersion monitoring for equalization in optical fiber communication systems

Critical issues that severely hamper high-bit-rate (≥10 Gbit/s/channel) and long-haul optical fiber communication systems include chromatic dispersion, polarization mode dispersion (PMD), and fiber nonlinearities. Optical fiber communication systems are designed such that these degrading effects are minimized.; A key challenge is that there are several factors in which cause these fiber-based effects to vary with time, including: (i) temperature changes will cause a shift in the accumulated chromatic dispersion and affect any polarization based impairment penalties, (ii) reconfigurable optical networking will alter the signal path and thus the accumulation of fiber-based effects, and (iii) periodic repair and maintenance of the fiber plant will alter the fiber itself. These time varying degradation effects necessitate a monitoring unit in an optical network in order to either dynamically tune a mitigator or determine the network location that must be diagnosed or repaired.; In addition, the main difficulty with managing and mitigating polarization effects in long distance fiber transmission systems is that they are stochastic processes. This means that a system can randomly wander in and out of high-penalty states. The goal, therefore, is to reduce the probability that the penalty will exceed an acceptable level to a negligible value (typically <1 minute per year). Outages caused by polarization effects are therefore non-catastrophic. This justifies the need for dynamic monitoring and mitigation techniques.; Therefore, for management, monitoring, and mitigation purposes in a robust system, simple, sensitive, flexible, and cost-effective chromatic dispersion and PMD monitoring technique may prove quite beneficial. Moreover, it may be highly desirable for component manufacturers and suppliers to be able to accurately measure the differential-group-delay (DGD) of devices and components to ensure that they are compliant with customer specifications.; In this dissertation, I propose and experimentally demonstrate several techniques to monitor these fiber dispersive effects (chromatic dispersion and PMD) by improving the monitoring control signal's requirements. We apply the proposed monitoring methods to different types of modulation formats and use some of them for optical compensation. In addition, we highlight two DGD measurement techniques. These techniques may potentially play key roles in future fiber-optic dynamic systems and reconfigurable optical networks.