TABLE OF CONTENTS Jonathan Sewter
Anthony Chan Carusone [1]
Edward S. Rogers Sr. Department of Electrical and Computer Engineering
University of Toronto
10 King's College Rd.
Toronto, Canada, M5S 3G4
An analysis of first-order polarization-mode dispersion (PMD) effects in a 40-Gb/s optical system is used to compare different electronic equalizer architectures as potential PMD compensators. Both linear and nonlinear equalizers are considered employing symbol-spaced and fractionally-spaced taps. It is found that a decision feedback equalizer consisting of a 3-tap symbol-spaced feedforward equalizer and a 1-tap feedback equalizer effectively eliminates PMD as the dominant length-limiting factor in most 40-Gb/s optical systems. Such an equalizer would entail less complexity than several previously reported electronic PMD compensators.
Keywords: optical communication, polarization mode dispersion, adaptive equalizer
[1]tcc@eecg.utoronto.ca
Optical communication systems have been used since the 1970s for high-volume data transmission within wide-area, metropolitan-area and local-area networks1. Until recently, long-haul links over single-mode fiber (SMF) could be designed without concern for the bandwidth limitations of the fiber. By compensating for fiber loss with amplifiers, the reach of these systems could be extended. To satiate the demand for greater network capacity, the data rate of current optical systems has been pushed to 10 and 40 Gb/s (OC-192 and OC-768). At these data rates, it is no longer possible to neglect the bandwidth limitations of SMF, as several dispersion mechanisms lead to frequency-dependent loss2.
The two most important dispersion mechanisms for SMF are chromatic dispersion (CD) and polarization-mode dispersion (PMD). CD is a result of...
