IEC 61300-3-38:2012 describes the measurement methods necessary to characterise the group delay properties of passive devices and dynamic modules. From these measurements further parameters like group delay ripple, linear phase deviation, chromatic dispersion, dispersion slope, and phase ripple can be derived. In addition, when these measurements are made with resolved polarization, the differential group delay can also be determined as an alternative to separate measurement with the dedicated methods of IEC 61300-3-32.<\/p>\n
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| 6<\/td>\n | English CONTENTS <\/td>\n<\/tr>\n | ||||||
| 9<\/td>\n | 1 Scope 2 Normative references 3 Terms and abbreviations <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | 4 General description <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 5 Apparatus 5.1 Modulation phase shift method 5.1.1 General 5.1.2 Variable wavelength source VWS 5.1.3 Tracking filter (optional) Figures Figure 1 \u2013 MPS measurement method apparatus <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | 5.1.4 Reference branching device RBD1, RBD2 5.1.5 Wavelength monitor (optional) 5.1.6 Device under test DUT 5.1.7 Detectors D1, D2 <\/td>\n<\/tr>\n | ||||||
| 13<\/td>\n | 5.1.8 RF generator 5.1.9 Amplitude modulator 5.1.10 Phase comparator 5.1.11 Temporary joints TJ1, TJ2 5.1.12 Polarization controller (optional) <\/td>\n<\/tr>\n | ||||||
| 14<\/td>\n | 5.1.13 Reference jumper 5.2 Swept wavelength interferometry method 5.2.1 General 5.2.2 Tunable laser source TLS Figure 2 \u2013 SWI measurement method apparatus <\/td>\n<\/tr>\n | ||||||
| 15<\/td>\n | 5.2.3 Wavelength monitor 5.2.4 Reference branching devices RBD1, RBD2, RBD3 5.2.5 Detectors D1, D2 5.2.6 Polarization controller 5.2.7 Polarization analyzer 5.3 Polarization phase shift method 5.3.1 General <\/td>\n<\/tr>\n | ||||||
| 16<\/td>\n | 5.3.2 Tunable laser source TLS 5.3.3 RF generator Figure 3 \u2013 PPS measurement method apparatus <\/td>\n<\/tr>\n | ||||||
| 17<\/td>\n | 5.3.4 Amplitude modulator 5.3.5 Polarization controller 5.3.6 Polarization splitter 5.3.7 Detectors D1, D2 <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 5.3.8 Amplitude and phase comparator 6 Measurement procedure 6.1 Modulation phase shift method 6.1.1 Measurement principle 6.1.2 RF modulation frequency <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | Table 1 \u2013 Modulation frequency versus wavelength resolution for C-band <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | 6.1.3 Test sequence Figure 4 \u2013 Sampling at the modulation frequency <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 6.1.4 Special notice for measurement of GDR 6.1.5 Calculation of relative group delay 6.2 Swept wavelength interferometry method 6.2.1 Measurement principle <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 6.2.2 Test sequence 6.2.3 Special notice for measurement of GDR 6.2.4 Calculation of group delay <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | 6.3 Polarization phase shift method 6.3.1 Modulation frequency <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | 6.3.2 Wavelength increment 6.3.3 Scanning wavelength and measuring CD 6.3.4 Calibration <\/td>\n<\/tr>\n | ||||||
| 25<\/td>\n | 6.3.5 Calculation of relative group delay and CD 6.4 Measurement window (common for all test methods) <\/td>\n<\/tr>\n | ||||||
| 26<\/td>\n | Figure 5 \u2013 Measurement window centred on an ITU wavelength with a defined width Figure 6 \u2013 Measurement window determined by the insertion loss curve at 3dB <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 7 Analysis 7.1 Noise reduction of group delay measurement 7.1.1 Averaging 7.1.2 Spectral filtering 7.2 Linear phase variation 7.3 Chromatic dispersion 7.3.1 General <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | 7.3.2 Finite difference calculation 7.3.3 Curve fit Figure 7 \u2013 Calculated CD from fitted GD over a 25 GHz optical BW centredon the ITU frequency <\/td>\n<\/tr>\n | ||||||
| 29<\/td>\n | 7.4 Phase ripple 7.4.1 General 7.4.2 Slope fitting 7.4.3 GDR estimation Figure 8 \u2013 A 6th order polynomial curve is fitted to relative GD data overa 25 GHz optical BW centred on the ITU frequency <\/td>\n<\/tr>\n | ||||||
| 30<\/td>\n | 7.4.4 Phase ripple calculation 8 Examples of measurement 8.1 50GHz band-pass thin-film filter Figure 9 \u2013 Estimation of the amplitude of the GD ripple and the period Figure 10 \u2013 GD and loss spectra for a 50\u00a0GHz-channel-spacing DWDM filter <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 8.2 Planar waveguide filter component Figure 11 \u2013 Measured GD and loss spectra for planar waveguide filter Figure 12 \u2013 Measured CD and loss spectra for planar waveguide filter <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | 8.3 Tunable dispersion compensator (fiber bragg grating) 8.4 Random polarization mode coupling device Figure 13 \u2013 Measured GD deviation of a fibre Bragg grating Figure 14 \u2013 Measured phase ripple of a fibre Bragg grating <\/td>\n<\/tr>\n | ||||||
| 33<\/td>\n | 9 Details to be specified Figure 15 \u2013 Measured GD for a device with random polarization mode coupling Figure 16 \u2013 Measured CD for a device with random polarization mode coupling <\/td>\n<\/tr>\n | ||||||
| 34<\/td>\n | Annex A (informative) Calculation of differential group delay Figure A.1 \u2013 Mueller states on Poincar\u00e9 sphere <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | Table A.1 \u2013 Example of Mueller set <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | Figure A.2 \u2013 DGD spectrum for a 50\u00a0GHz bandpass filter,measured with 30\u00a0pm resolution BW <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | Figure A.3 \u2013 DGD versus wavelength for a random polarizationmode coupling device (example) Figure A.4 \u2013 DGD versus wavelength for a fibre Bragg grating filter (example) <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Fibre optic interconnecting devices and passive components. Basic test and measurement procedures – Examinations and measurements. Group delay, chromatic dispersion and phase ripple<\/b><\/p>\n |