Impact of Chromatic and Polarization-Mode Dispersions on DPSK Systems Using Interferometric Demodulation and Direct Detection

J. Wang, J.M. Kahn
2004 Journal of Lightwave Technology  
We study the impact of chromatic dispersion (CD) and polarization-mode dispersion (PMD) on systems using binary or quaternary differential phase-shift keying (2-DPSK or 4-DPSK) with non-returnto-zero (NRZ) or return-to-zero (RZ) formats. These signals are received using optical preamplification, interferometric demodulation and direct detection. We consider the linear propagation regime, and compute optical power penalties at fixed bit-error rate (BER). In order to evaluate the BER precisely
more » ... he BER precisely taking account of amplifier noise, arbitrary pulse shapes, arbitrary optical and electrical filtering, CD and PMD, we introduce a novel model for DPSK systems and compute the BER using a method recently proposed by Forestieri for on-off keying (OOK) systems. We show that when properly applied, the method yields highly accurate results for DPSK systems. We have found that NRZ-2-DPSK exhibits power penalties similar to NRZ-OOK in the presence of CD and PMD. NRZ-4-DPSK, as it has twice the symbol duration of these other techniques for a given bit rate, incurs CD and PMD power penalties only about one quarter as large as NRZ-2-DPSK. RZ-2-DPSK, as compared to NRZ-2-DPSK, incurs smaller penalties due to PMD, but offers no advantage in terms of CD. RZ-4-DPSK offers CD and PMD penalties significantly smaller than all other techniques.
doi:10.1109/jlt.2003.822101 fatcat:pesz2nv2o5bk3dq3aixq5y3fvq