Open AccessFree spectral range optimization of return-to-zero differential phase-shift keyed demodulation in 40 Gbit/s nonlinear transmission
Author(s) -
Xiaolin Li,
Fan Zhang,
Xiaoru Zhang,
Dechao Zhang,
Zhangyuan Chen,
Anshi Xu
Publication year - 2008
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.16.002056
Subject(s) - demodulation , optics , physics , free spectral range , self phase modulation , transmission (telecommunications) , phase modulation , bandwidth (computing) , interferometry , bit error rate , differential phase , phase (matter) , nonlinear optics , computer science , telecommunications , decoding methods , phase noise , laser , channel (broadcasting) , quantum mechanics
For differential decoding, direct detection of DPSK signal needs a delay line interferometer with a free spectral range normally equal to the transmitted bit-rate. We numerically demonstrate that free spectral range optimization can increase tolerance to fiber Kerr nonlinearities for 40 Gbit/s RZ-DPSK transmission, especially for multi-format (RZ-DPSK and RZ-OOK) systems, in which Kerr nonlinearities is quite serious mainly due to cross-phase modulation. The optimal delay time of the delay line interferometer in DPSK signal demodulation is shorter than one bit-period. Joint optimization of free spectral range and optical filter bandwidth will further enhance system tolerance to nonlinear transmission.