| For ≥10-Gbit/s bit rates that are transmitted over ≥100 km, it is essential that chromatic dispersion be well managed by using some type of dispersion compensation. Since the required accuracy in dispersion compensation increases dramatically with the bit rate, the use of tunable modules is the only way of managing accumulated dispersion in 40-Gbit/s systems. For tunable dispersion compensation, some methods of dispersion monitoring have also to be implemented. Monitoring that is simple, and accurate would facilitate robust performance when combined with tunable dispersion compensators.; After managing fiber dispersion and nonlinearities, the capacity of optical systems has been greatly expanded over the past few years. However, polarization mode dispersion (PMD) has recently emerged as one of the next critical hurdles. As system carriers attempt to deploy 40-Gbit/s optical networks, PMD becomes the biggest challenge even using the new fiber with pretty low PMD (<0.25 ps/km½).; The following techniques to solve these fiber dispersive effects are presented in this dissertation: (i) real-time group-velocity chromatic dispersion monitoring and automated compensation without modifying the transmitter, (ii) on-line dispersion monitoring and compensation using a single in-band subcarrier tone, (iii) on-line effective higher-order PMD monitoring of non-return to zero (NRZ) data by clock regenerating effect, (iv) 40-Gbit/s single channel transmission systems using a nonlinearly-chirped fiber Bragg grating (NC-FBG) for the tunable dispersion compensation, (v) 40-Gbit/s multi-channel tunable dispersion compensation using a single sampled NC-FBG, (vi) tunable intra-channel third-order dispersion free chromatic dispersion compensation using two inverse sampled NC-FBG for 4 x 40-Gbit/s system, (vii) adjustable chromatic dispersion-free differential group delay (DGD) compensation using high birefringence nonlinearly-chirped fiber Bragg gating, (viii) intra-bit polarization diversity modulation for PMD mitigation, (ix) fast XPM-induced polarization-state fluctuations in wavelength-division-multiplexing (WDM) systems and their mitigation, (x) chromatic dispersion and PMD impairments and their monitoring for differential phase-shift-keyed (DPSK) modulation format. These techniques will play key roles in future robust optical dynamic systems and reconfigurable networks. |
