This part of IEC 61746 provides procedures for calibrating single-mode optical time domain reflectometers (OTDR). It only covers OTDR measurement errors and uncertainties.<\/p>\n
This standard does not cover correction of the OTDR response.<\/p>\n
| PDF Pages<\/th>\n | PDF Title<\/th>\n<\/tr>\n | ||||||
|---|---|---|---|---|---|---|---|
| 6<\/td>\n | CONTENTS <\/td>\n<\/tr>\n | ||||||
| 10<\/td>\n | INTRODUCTION <\/td>\n<\/tr>\n | ||||||
| 11<\/td>\n | 1 Scope 2 Normative references 3 Terms, definitions and symbols <\/td>\n<\/tr>\n | ||||||
| 12<\/td>\n | Figures Figure 1 \u2013 Definition of attenuation dead zone <\/td>\n<\/tr>\n | ||||||
| 18<\/td>\n | 4 Preparation for calibration 4.1 Organization 4.2 Traceability 4.3 Preparation 4.4 Test conditions 4.5 Documentation <\/td>\n<\/tr>\n | ||||||
| 19<\/td>\n | 5 Distance calibration \u2013 General 5.1 General 5.2 Location deviation model <\/td>\n<\/tr>\n | ||||||
| 20<\/td>\n | Figure 2 \u2013 Representation of the location deviation \u0394L(L) <\/td>\n<\/tr>\n | ||||||
| 21<\/td>\n | 5.3 Using the calibration results 5.4 Measuring fibre length <\/td>\n<\/tr>\n | ||||||
| 22<\/td>\n | 6 Distance calibration methods 6.1 General 6.2 External source method <\/td>\n<\/tr>\n | ||||||
| 23<\/td>\n | Figure 3 \u2013 Equipment for calibration of the distance scale \u2013 External source method <\/td>\n<\/tr>\n | ||||||
| 24<\/td>\n | Figure 4 \u2013 Set-up for calibrating the system insertion delay <\/td>\n<\/tr>\n | ||||||
| 27<\/td>\n | 6.3 Concatenated fibre method <\/td>\n<\/tr>\n | ||||||
| 28<\/td>\n | Figure 5 \u2013 Concatenated fibres used for calibration of the distance scale <\/td>\n<\/tr>\n | ||||||
| 31<\/td>\n | 6.4 Recirculating delay line method <\/td>\n<\/tr>\n | ||||||
| 32<\/td>\n | Figure 6 \u2013 Distance calibration with a recirculating delay line Figure 7 \u2013 OTDR trace produced by recirculating delay line <\/td>\n<\/tr>\n | ||||||
| 35<\/td>\n | 7 Loss calibration \u2013 General 7.1 General 7.2 Determination of the displayed power level F <\/td>\n<\/tr>\n | ||||||
| 36<\/td>\n | 7.3 Selection of an appropriate reference loss Aref Figure 8 \u2013 Determining the reference level and the displayed power level <\/td>\n<\/tr>\n | ||||||
| 37<\/td>\n | 7.4 Development of a test plan Figure 9 \u2013 Measurement of the OTDR loss samples Table 1 \u2013 Attenuation coefficients defining region A <\/td>\n<\/tr>\n | ||||||
| 38<\/td>\n | Figure 10 \u2013 Region A, the recommended region for loss measurement samples Figure 11 \u2013 Possible placement of sample points within region A <\/td>\n<\/tr>\n | ||||||
| 39<\/td>\n | 7.5 Polarization dependence Figure 12 \u2013 External source method for testing the polarization dependence of the OTDR Figure 13 \u2013 Reflection method for testing the polarization dependence of the OTDR <\/td>\n<\/tr>\n | ||||||
| 40<\/td>\n | 7.6 Calculation of the calibration results 7.7 Using the calibration results 8 Loss calibration methods 8.1 General <\/td>\n<\/tr>\n | ||||||
| 41<\/td>\n | 8.2 Fibre standard method Figure 14 \u2013 Loss calibration with a fibre standard <\/td>\n<\/tr>\n | ||||||
| 42<\/td>\n | Figure 15 \u2013 Placing the beginning of section D1 outside the attenuation dead zone <\/td>\n<\/tr>\n | ||||||
| 44<\/td>\n | 8.3 External source method (see Figure 16) <\/td>\n<\/tr>\n | ||||||
| 45<\/td>\n | Figure 16 \u2013 Loss calibration with the external source method <\/td>\n<\/tr>\n | ||||||
| 46<\/td>\n | Figure 17 \u2013 Location and measurements for external source method <\/td>\n<\/tr>\n | ||||||
| 48<\/td>\n | 8.4 Splice simulator method Figure 18 \u2013 Set-up for loss calibration with splice simulator <\/td>\n<\/tr>\n | ||||||
| 49<\/td>\n | Figure 19 \u2013 OTDR display with splice simulator <\/td>\n<\/tr>\n | ||||||
| 50<\/td>\n | Figure 20 \u2013 Measurement of the splice loss <\/td>\n<\/tr>\n | ||||||
| 52<\/td>\n | 8.5 Power reduction method <\/td>\n<\/tr>\n | ||||||
| 53<\/td>\n | Figure 21 \u2013 Loss calibration with “fibre-end” variant of the power reduction method <\/td>\n<\/tr>\n | ||||||
| 54<\/td>\n | Figure 22 \u2013 Loss calibration with “long-fibre” variant of the power reduction method <\/td>\n<\/tr>\n | ||||||
| 56<\/td>\n | 9 Reflectance calibration 9.1 Objective 9.2 Reflectance measurements (see Figure 23) 9.3 Use of the backscatter parameter, K Figure 23 \u2013 Parameters involved in reflectance measurements <\/td>\n<\/tr>\n | ||||||
| 57<\/td>\n | 9.4 Range of reflectance measurement Figure 24 \u2013 The same reflectance at the end of three fibres with different values of the backscatter parameter shows different pulse amplitudes <\/td>\n<\/tr>\n | ||||||
| 58<\/td>\n | 9.5 Development of a test plan Figure 25 \u2013 Maximum and minimum values for the pulse amplitude, \u0394F Figure 26 \u2013 Range of reflectance measurement <\/td>\n<\/tr>\n | ||||||
| 59<\/td>\n | 9.6 Equipment Figure 27 \u2013 Determining the default displayed power level and the default location <\/td>\n<\/tr>\n | ||||||
| 60<\/td>\n | 9.7 Measurement procedure Figure 28 \u2013 Set-up for reflectance calibration <\/td>\n<\/tr>\n | ||||||
| 62<\/td>\n | Annex A (normative) Recirculating delay line for distance calibration Figure A.1 \u2013 Recirculating delay line <\/td>\n<\/tr>\n | ||||||
| 63<\/td>\n | Figure A.2 \u2013 Measurement set-up for loop transit time Tb <\/td>\n<\/tr>\n | ||||||
| 64<\/td>\n | Figure A.3 \u2013 Calibration set-up for lead-in transit time Ta <\/td>\n<\/tr>\n | ||||||
| 66<\/td>\n | Annex B (normative) Optical fibre standard for loss calibration <\/td>\n<\/tr>\n | ||||||
| 67<\/td>\n | Figure B.1 \u2013 Determination of a highly linear power range <\/td>\n<\/tr>\n | ||||||
| 68<\/td>\n | Figure B.2 \u2013 Testing the longitudinal backscatter uniformity of the fibre standard <\/td>\n<\/tr>\n | ||||||
| 70<\/td>\n | Annex C (normative) Standard splice simulator for loss calibration Figure C.1 \u2013 Splice simulator and idealized OTDR signature <\/td>\n<\/tr>\n | ||||||
| 72<\/td>\n | Figure C.2 \u2013 Determination of the reference loss Aref <\/td>\n<\/tr>\n | ||||||
| 74<\/td>\n | Annex D (normative) Mathematical basis <\/td>\n<\/tr>\n | ||||||
| 77<\/td>\n | Annex E (normative) Reflectance standard Figure E.1 \u2013 Reflectance standard description and trace <\/td>\n<\/tr>\n | ||||||
| 80<\/td>\n | Figure E.2 \u2013 Calibration set up and reference points for calibration <\/td>\n<\/tr>\n | ||||||
| 83<\/td>\n | Annex F (normative) Simple version of reflectance standard Figure F.1 \u2013 Reflectance standard description and trace <\/td>\n<\/tr>\n | ||||||
| 85<\/td>\n | Figure F.2 \u2013 Calibration set up and reference points for calibration <\/td>\n<\/tr>\n | ||||||
| 87<\/td>\n | Annex G (informative) OTDR basis: Backscatter theory \u2013 Reflectance measurements using an OTDR \u2013 Determination of fibre backscatter parameter <\/td>\n<\/tr>\n | ||||||
| 88<\/td>\n | Figure G.1 \u2013 OTDR signals used for determining reflectance <\/td>\n<\/tr>\n | ||||||
| 90<\/td>\n | Figure G.2 \u2013 Set-up for measurement of the backscatter coefficient <\/td>\n<\/tr>\n | ||||||
| 92<\/td>\n | Bibliography <\/td>\n<\/tr>\n<\/table>\n","protected":false},"excerpt":{"rendered":" Calibration of optical time-domain reflectometers (OTDR) – OTDR for single-mode fibres<\/b><\/p>\n |