Impairments in Polarization-Multiplexed DWDM Channels due to Cross- Polarization Modulation Marcus...
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Transcript of Impairments in Polarization-Multiplexed DWDM Channels due to Cross- Polarization Modulation Marcus...
Impairments in Polarization-Multiplexed DWDM Channels due to Cross-
Polarization Modulation
Marcus WinterChristian-Alexander Bunge
Klaus Petermann
Hochfrequenztechnik-Photonik
TECHNISCHEUNIVERSITÄTBERLIN
Dario Setti
http://www.marcuswinter.de/publications/leos2008
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
cross-polarization modulation(XPolM)
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
XPolM is a nonlinear interchannel effect whichrandomly rotates the polarization states in time
similar to how XPM affects the phase
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
nonlinear polarization effects
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
distribution of SOPs of a CW probe channelpropagation of 10 spans with 10 × 10 Gbps NRZ interfering channels
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
distribution of SOPs of a CW probe channelpropagation of 10 spans with 10 × 10 Gbps NRZ interfering channels
DOP = 0.894
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
θ is the „deflection“ from the mean directionφ is the azimuth
average SOP
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
impairments in PolDM systems
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
PolDM subchannel is originally (on average)x-polarized
symbol SOP is rotated through XPolM by an angle θ (in Stokes space) from the mean
fading
crosstalk
Jones spacevisualization
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
crosstalk
fading
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
crosstalk from a single CW channel into orthogonal (y-)polarization
DOP = 0.894
crosstalk phase depends on azimuth φ in Stokes space
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
fading within a single CW channel(x-polarization)
DOP = 0.894
fading
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
crosstalk variance vs. CW DOP reduction
valid only for the polarization / PMD ensemble
only the ensemble statistics of the SOPs are known
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
system simulations
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
PolDM’ed (low-power) CW probe and QPSK signal +10 × 10 Gbps NRZ interferers
PolDM DEMUX is aligned to mean CW probe SOP
determination of I and Q ROSNR as if it werean (all-zero) 10 Gbaud DQPSK signal
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Fachgebiet Hochfrequenztechnik
CW subchannel only
– variations are caused by XPM no dependence on DOP
500 iterations with random polarization parameters / NRZ bit patterns
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
large ROSNR variation due to non-Gaussian crosstalk within individual members of the ensemble
significant dependence on DOP
CW probe w/ QPSK PolDM neighbor
500 iterations with random polarization parameters / NRZ bit patterns
analytical estimate using Gaussian crosstalk distribution
and variance
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
summary and conclusions
TECHNISCHEUNIVERSITÄTBERLIN
Fachgebiet Hochfrequenztechnik
XPolM-induced depolarization leads to crosstalk between and fading within PolDM subchannels
crosstalk added at the PolDM demultiplexer is Gaussian distributed and predictable (in the statistical average)
individual realizations within the statisticalensemble can be significantly non-Gaussian
large variation of observed system penalties
outage statistics required for a more accurate description