Open AccessMeasurement of PMD tolerance in 40-Gb/s polarization-multiplexed RZ-DQPSK
Author(s) -
Pierpaolo Boffi,
Maddalena Ferrario,
L. Marazzi,
Paolo Martelli,
Paola Parolari,
A. Righetti,
R. Siano,
Mario Martinelli
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.16.013398
Subject(s) - polarization mode dispersion , phase shift keying , optics , differential group delay , physics , multiplexing , bit error rate , wavelength division multiplexing , polarization division multiplexing , polarization (electrochemistry) , computer science , optical fiber , telecommunications , wavelength , decoding methods , chemistry
We experimentally investigate the first-order polarization-mode dispersion (PMD) tolerance of two polarization-multiplexed (POLMUX) RZ-DQPSK signals at overall 40 Gb/s. The polarization demultiplexing is enabled by an automatic endless polarization stabilizer. Time-interleaving the two orthogonally polarized RZ-DQPSK signals minimizes the crosstalk due to the non-ideal polarization stabilization, while it represents the worstcase for the PMD-induced crosstalk. Bit-error rate measurements are performed both in back-to-back and after 25-km standard single-mode fiber. The PMD tolerance is evaluated as a function of the instantaneous differential group delay, introduced by a first-order PMD emulator. 40-Gb/s POLMUX RZ-DQPSK is more sensitive to PMD than single-polarization 20-Gb/s DQPSK, while it is more PMD-tolerant than 40-Gb/s NRZ-OOK. Besides, its chromatic dispersion robustness is similar to the single-polarization 20-Gb/s DQPSK. The combination of POLMUX and DQPSK is therefore very promising in view of transmission systems at high bit-rate.