Coding Design for Fiber-Coding Design for Fiber-Optic PolDM SystemsOptic PolDM Systems

Chunpo PanSupervisor: Prof. Frank Kschischang

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IntroductionIntroduction

Telephone Signal

Internet Signal

Cable TV Signal

On-off keying: spectral efficiency is only 0.8 b/s/Hz!

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To Increase Spectral To Increase Spectral EfficiencyEfficiencyNoncoherent Detection to

Coherent Detection

Polarization-Division Multiplexing (PolDM)

Im

Re

Im

Re

Im

Re

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PolDM Systems in PolDM Systems in LiteraturesLiteratures

RZ-DPSK

CSRZ-DPSK

RZ-DQPSK

RZ-8PSK

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ImpairmentsImpairmentsNonlinear impairments:Kerr nonlinearityo The higher the intensity, the greater the nonlinearity

is

o Will induce nonlinear phase noise (NLPN)

Linear impairments:Polarization mode dispersion (PMD) dominates!

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PMDPMD

Slow axis

Fast axis

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Time varying on the scale of milliseconds

!Current compensators are

complicated and expensive to build.

DPTC without PMD DPTC without PMD compensationcompensation

HA unitary matrix!

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An analogue to wireless MIMO system

Wireless SystemDifferential Space-Time Coding (DSTC)

PolDM SystemDifferential Polarization-Time Coding (DPTC)

DPTCDPTC

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is a 2x2 unitary group.

Simulation ResultsSimulation Results

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Simulation ResultsSimulation Results

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Standard receiver

DPTC 64

pointsElectroni

c equalizer

Optical PMDC

Coherent PolDM-QPSK

Digital MLSE