Tham khảo tài liệu 'optical fiber communications and devicesan incorrectly part 13', kỹ thuật - công nghệ, cơ khí - chế tạo máy phục vụ nhu cầu học tập, nghiên cứu và làm việc hiệu quả | 290 Optical Fiber Communications and Devices Fig. 9. Power penalty as a function of the mean DGD for an NRZ system. The solid line shows results for this system with optimized filter bandwidths in the absence of PMD. The dashed line shows results for the optimized filters for 10-5 outage probability in a system with mean DGD of 10 ps 10 of the bit period . 4. Conclusions We used laboratory experiments and Monte Carlo simulations to show how one can use a semi-analytical receiver model to accurately calculate the Q factor for systems with arbitrary optical pulse shapes arbitrary receiver characteristics and arbitrary polarized noise. Our results showed that the system variation caused by partially polarized noise depends not only on the angle between the signal and polarized part of the noise but also on the DOP of the noise. Highly polarized noise will cause larger variation in the system performance. Our results suggest that in order to reduce the variation of the system performance one needs to keep the noise unpolarized. The receiver model that we developed is also used to determine the performance degradation due to intra-channel PMD in optical fiber communication systems and to show that the receiver filter bandwidths optimized for optical fiber systems at 10-5 outage probability due to PMD are very close to the ones optimized for the same systems in the absence of PMD. We observed that the PMD-induced waveform distortions significantly reduce the robustness of the RZ formats to the receiver characteristics. The receiver model that we developed can also be used to efficiently determine the performance degradation of optical fiber communication systems due to the combination of inter-channel PMD and PDL using the simplified reduced Stokes model. 5. Acknowledgment The author thanks Dr. Yu Sun and Dr. Ivan Lima Jr. for helpful discussions and for allowing the results of joint publications with the author Dr. Aurenice Oliveira to be used in this book chapter. 291
