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Quasi-light Storage for Optical Data Packets
Published on: February 6, 2014
Bit-error rate performance of coherent optical M-ary PSK/QAM using decision-aided maximum likelihood phase estimation
Changyuan Yu1, Shaoliang Zhang, Pooi Yuen Kam
1Department of Electrical & Computer Engineering, National University of Singapore, 117576 Singapore.
Optics Express
|July 1, 2010
Summary
This study analyzes phase error impacts on 16-phase-shift keying (PSK) and 16-quadrature amplitude modulation (QAM) bit-error rate (BER). 16-QAM shows superior laser linewidth tolerance compared to 16-PSK for high spectral efficiency in optical communications.
Area of Science:
- Optical Communications
- Digital Signal Processing
- Modulation Formats
Background:
- Phase errors significantly degrade the performance of modulation schemes like PSK and QAM.
- Accurate bit-error rate (BER) analysis is crucial for designing robust optical communication systems.
- Understanding laser linewidth tolerance is essential for high-speed optical transmissions.
Purpose of the Study:
- To analytically derive BER expressions for 16-PSK and 16-QAM in the presence of phase errors.
- To examine the performance penalty as a function of phase error variance.
- To predict laser linewidth tolerance for various modulation formats and compare 16-QAM with other schemes.
Main Methods:
- Analytical derivation of BER expressions for 16-PSK and 16-QAM.
- Averaging BER over phase error statistics to analyze performance penalty.
- Extending phase error variance analysis to 16-QAM and comparing with Monte Carlo simulations.
- Developing approximate BER expressions for quick performance estimation.
Main Results:
- Phase error variances leading to a 1-dB SNR penalty at BER=10(-4) were quantified for various modulation formats.
- Laser linewidth tolerance was predicted and validated against simulations.
- 16-QAM demonstrated better laser linewidth tolerance than 16-PSK at the same spectral efficiency.
- 16-QAM performance was comparable to 8-PSK despite higher spectral efficiency.
Conclusions:
- 16-QAM is a promising modulation format for high spectral efficiency coherent optical communications due to its favorable laser linewidth tolerance.
- The developed analytical expressions and methods allow for accurate prediction of BER performance and linewidth requirements.
- The findings provide valuable insights for the design and optimization of future optical communication systems.
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