Pulsed Measurement of PMD in Field-Installed Optical Fibers

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Pulsed Measurement of PMD in Field-Installed
Optical Fibers

• A.O. Kleivstul, Telenor RD
• A.S. Sudbø, University of Oslo Graduate Center at
  Kjeller

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PMD Measurements in the FieldOutline of Talk

• Fixed Analyzer (FA) Method
• One-way and two-way measurements
• FA Method with OTDR. Many fibers
• Field measurement results
• Comparison One- and two-way
• Conclusion

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FA Method, One-way
Fiber
TunableLaser
PowerMeter
4
FA Method, Two-Way
Fiber
PowerMeter
TunableLaser
5
FA Method Polarization Analyzed Spectral
Response (PASR) of Fiber
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Measurement Uncertainty(Ideal Random Coupling)
frequency interval

• tPMD Mean (DtDGD)
• Var (DtDGD) 0.129 tPMD/Dn

• 0.25
  Ne2W /Dn
• Var (DtFA2W) 0.19 tPMD/Dn

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Tuneable OTDR Measures Several Fibers
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OTDR Measurement Results
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OTDR Measurement Results
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Pulsed FA methodPASR obtained from pulse height
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Measuremant Setup (One-way)
Fibers
Modulator
Pol.
Return fiber
c
OTDR
Computer
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Measurement Setup (Two-Way)
Fibers
Modulator
Pol.
c
OTDR
Computer
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Measurement Setup (Two-Way)
Fibers
Modulator
c
OTDR
Computer
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OTDR measurements with polarizer
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Tuneable OTDR methodPASR obtained from pulse
height
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Conclusions

• Tuneable OTDR with polarizer well suited for
  surveying PMD on installed fiber cables
• Many fibers may be connected to one OTDR and
  measured in parallell
• One-way method Better signal-to-noise ratio,
  shorter measurement time
• Two-way method No need to travel to far end (?)