PMD Measurement Methods

1. PMD Measurement Methods Fixed Analyzer Method IEC 60793-1-48/ ITU-T G.650.2/ EIA/TIA Standard FOTP-113 Jones Eigenanalysis Matrix Method IEC 60793-1-48/ ITU-T G.650.2/ TIA/EIA Standard FOTP-122A Traditional Interferometric Method IEC 60793-1-48/ ITU-T G.650.2/ TIA/EIA Standard FOTP-124A General Interferometric Method IEC 60793-1-48/ ITU-T G.650.2/ TIA/EIA Standard FOTP-124A Poincare Sphere Method (not presented)? Laboratory use only State of Polarization method (Not presented)? Laboratory use only Simple calculation Addition of the root square of the PMD of each section P-OTDR method Not approved

2. Fixed-Analyzer Method

3. Fixed-Analyzer Method FFT compared to extrema counting: Filters out high frequency features (noise, vibrations)? Gives graphical indication of the mode coupling characteristics FFT compared to extrema counting: Filters out high frequency features (noise, vibrations)? Gives graphical indication of the mode coupling characteristics

4. Fixed Analyzer Method

5. Fixed-Analyzer Method Other advantages: Low cost solution 3 functions possible in one: PMD, OSA and Attenuation Profile Other drawbacks: Limited to relatively small PMD because of the OSA resolution (<60ps). The lower limit is defined by the wavelength range of the source and the wavelength range of the OSA (0,05ps). The fixed analyzer method requires high power light source, with high cost, to reach significant dynamic range. Mode coupling must be taken into consideration when performing the test Other advantages: Low cost solution 3 functions possible in one: PMD, OSA and Attenuation Profile Other drawbacks: Limited to relatively small PMD because of the OSA resolution (<60ps). The lower limit is defined by the wavelength range of the source and the wavelength range of the OSA (0,05ps). The fixed analyzer method requires high power light source, with high cost, to reach significant dynamic range. Mode coupling must be taken into consideration when performing the test

6. Jones Matrix Eigenanalysis Method The calculation of the Jones Matrix is made thanks to 3 known states of linearity polarized light A,B and C.The calculation of the Jones Matrix is made thanks to 3 known states of linearity polarized light A,B and C.

7. Jones Matrix Eigenanalysis Method

8. Interferometric method (TINTY)? A polarized broadband signal is sent over the Fiber Under Test and passes an interferometer, where it is split into both interferometer arms and polarized orthogonally to each other, before it hits the detector. The interference fringes are measured with the time delay introduced by moving the variable mirror of the interferometer over a wide enough range. To obtain the PMD from the interferogram in the random mode coupling, it is fit to a mathematical model, most of the time a Gaussian curve. The PMD can be obtained from the standard deviation of the fitted curve. A polarized broadband signal is sent over the Fiber Under Test and passes an interferometer, where it is split into both interferometer arms and polarized orthogonally to each other, before it hits the detector. The interference fringes are measured with the time delay introduced by moving the variable mirror of the interferometer over a wide enough range. To obtain the PMD from the interferogram in the random mode coupling, it is fit to a mathematical model, most of the time a Gaussian curve. The PMD can be obtained from the standard deviation of the fitted curve.

9. Interferometric method (TINTY)? Other drawbacks Upper measurement limit defined by the scan range of the adjustable arm of the interferometer. The scan range must be three times larger than the mean DGD value. Lower limit defined by the spectral width of the source and by the orthogonality of the interferometer arms. Not possible to use pigtails and launch cables, as interference effects due to reflections should be avoided. Mode coupling must be taken into consideration when performing the test Large PMD measurement requires enough mirror moving. Gaussian power distribution light source mandatory. Can�t use any SLED typeOther drawbacks Upper measurement limit defined by the scan range of the adjustable arm of the interferometer. The scan range must be three times larger than the mean DGD value. Lower limit defined by the spectral width of the source and by the orthogonality of the interferometer arms. Not possible to use pigtails and launch cables, as interference effects due to reflections should be avoided. Mode coupling must be taken into consideration when performing the test Large PMD measurement requires enough mirror moving. Gaussian power distribution light source mandatory. Can�t use any SLED type

10. Interferometric method (GINTY)?

11. Interferometric method (GINTY)? Other advantages Wide measurement range: from 0 to 115 ps Averaging not necessary No auto-correlation peak : accuracy and resolution increased Any spectral shape source can be used Other drawbacks Upper measurement limit defined by the scan range of the adjustable arm of the interferometer Must be careful when using pigtails and launch cables, as interference effects due to reflections should be avoided. For that, it is preferred to use index matching materials or angled cleaves Mode coupling must be taken into consideration when performing the test Large PMD measurement requires enough mirror moving.Other advantages Wide measurement range: from 0 to 115 ps Averaging not necessary No auto-correlation peak : accuracy and resolution increased Any spectral shape source can be used Other drawbacks Upper measurement limit defined by the scan range of the adjustable arm of the interferometer Must be careful when using pigtails and launch cables, as interference effects due to reflections should be avoided. For that, it is preferred to use index matching materials or angled cleaves Mode coupling must be taken into consideration when performing the test Large PMD measurement requires enough mirror moving.