Three-chip differential phase-shift keying maximum likelihood sequence estimation for chromatic-dispersion and...

Area of Science:

• Optical communications
• Signal processing

Background:

• Chromatic dispersion (CD) and first-order polarization-mode-dispersion (PMD) degrade optical signal quality.
• Extending transmission reach in differential phase-shift keying (DPSK) systems requires effective CD and PMD compensation.

Purpose of the Study:

• To introduce a novel three-chip DPSK maximum likelihood sequence estimation (MLSE) algorithm.
• To enhance the compensation capabilities for CD and PMD in DPSK signals.
• To extend the transmission reach of DPSK signals.

Main Methods:

• The proposed three-chip DPSK MLSE algorithm analyzes phase differences between adjacent and one-bit-apart optical bits.
• This method searches for the most probable path in the trellis for DPSK data sequence estimation.
• Performance is evaluated through simulations and comparisons with conventional two-chip DPSK MLSE.

Main Results:

• The three-chip DPSK MLSE significantly outperforms the conventional two-chip DPSK MLSE in CD and PMD compensation.
• CD tolerance for a 10 Gbit/s DPSK signal is enhanced by 2.5 times compared to the two-chip MLSE.
• A penalty of 1.4 dB is bounded for a differential group delay of 100 ps.

Conclusions:

• The proposed three-chip DPSK MLSE offers superior performance for CD and PMD compensation.
• This technique effectively extends the transmission reach of DPSK signals in optical networks.
• The enhanced compensation capabilities pave the way for higher data rates and longer-haul communication systems.