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Blind adaptive equalization of polarization-switched QPSK modulation
1Department of Electronic and Electrical Engineering, University College London (UCL), London, UK. d.millar@ee.ucl.ac.uk
Optics Express
|June 7, 2011
Summary
This study introduces a new algorithm for polarization-switched quaternary phase shift keying (PS-QPSK) optical signals. The blind adaptive equalization method ensures robust performance despite polarization impairments.
Area of Science:
- Optical Communications
- Digital Signal Processing
- Signal Equalization
Background:
- Coherent detection and digital signal processing have advanced optical communication capacity.
- Four-dimensional optical signal constellations are now detectable.
- Polarization-switched quaternary phase shift keying (PS-QPSK) is a key modulation format.
Purpose of the Study:
- To propose and investigate a blind adaptive equalization algorithm for PS-QPSK.
- To address the challenges of signal impairments in high-capacity optical systems.
Main Methods:
- Development of a blind adaptive equalization algorithm.
- Algorithm includes blind initialization and equalizer adaptation.
- Testing the algorithm's performance under various polarization conditions.
Main Results:
- The proposed algorithm is insensitive to input polarization state.
- Demonstrates robust convergence in the presence of polarization-dependent loss (PDL), differential group delay (DGD), and polarization rotation.
- Effective equalization of PS-QPSK signals.
Conclusions:
- The developed blind adaptive equalization algorithm is effective for PS-QPSK.
- The algorithm offers high robustness against common optical signal impairments.
- Enables reliable detection of advanced modulation formats in optical systems.
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