Exploiting the Faster-Than-Nyquist Concept in Wavelength-Division Multiplexing Systems Using Duobinary Shaping
Journal article, 2012
This paper begins with Nyquist wavelength-division multiplexing (WDM) and then introduces faster-than-Nyquist. In faster-than-Nyquist, a certain amount of inter-symbol interference (ISI) is accepted, which violates the fundamental principle of Nyquist WDM. This results in much-relaxed transceiver bandwidth and simpler spectral design. However, in faster-than-Nyquist, implementation complexity is shifted from the transmitter side to the receiver side. Therefore, successful application of faster-than-Nyquist depends on innovation in the receiver structure. In this paper, we discuss the guidelines for implementing suboptimum, low-complexity receivers based on faster-than-Nyquist. We suggest that duobinary shaping is a good technique for trading off achievable spectral efficiency, detection performance, and implementation complexity and might be preferable to Nyquist WDM. Experiments are conducted to verify robustness of the proposed technique.
wavelength division multiplexing
digital signal processing
optical fiber communications