BS EN IEC 60793-1-41:2024
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Optical fibres – Measurement methods and test procedures. Bandwidth
Published By | Publication Date | Number of Pages |
BSI | 2024 | 36 |
IEC 60793-1-41:2024 is available as IEC 60793-1-41:2024 RLV which contains the International Standard and its Redline version, showing all changes of the technical content compared to the previous edition.IEC 60793-1-41:2024 describes three methods for determining and measuring the modal bandwidth of multimode optical fibres (see IEC 60793-2-10, IEC 60793-2-30, and the IEC 60793?2?40 series). The baseband frequency response is directly measured in the frequency domain by determining the fibre response to a sinusoidaly modulated light source. The baseband response can also be measured by observing the broadening of a narrow pulse of light. The calculated response is determined using differential mode delay (DMD) data. The three methods are: Method A – Time domain (pulse distortion) measurement Method B – Frequency-domain measurement Method C – Overfilled launch modal bandwidth calculated from differential mode delay (OMBc) Method A and method B can be performed using one of two launches: an overfilled launch (OFL) condition or a restricted mode launch (RML) condition. Method C is only defined for A1-OM3 to A1-OM5 multimode fibres and uses a weighted summation of DMD launch responses with the weights corresponding to an overfilled launch condition. The relevant test method and launch condition is chosen according to the type of fibre. NOTE 1?These test methods are commonly used in production and research facilities and are not easily accomplished in the field. NOTE 2?OFL has been used for the modal bandwidth value for LED-based applications for many years. However, no single launch condition is representative of the laser (e.g. VCSEL) sources that are used for gigabit and higher rate transmission. This fact drove the development of IEC 60793-1-49 for determining the effective modal bandwidth of laser optimized 50 µm fibres. See IEC 60793-2-10 and IEC 61280-4-1 for more information. This fourth edition cancels and replaces the third edition published in 2010. This edition constitutes a technical revision. This edition includes the following significant technical changes with respect to the previous edition: a) the addition of a direct reference for method A and method B.
PDF Catalog
PDF Pages | PDF Title |
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2 | undefined |
5 | Annex ZA (normative)Normative references to international publicationswith their corresponding European publications |
6 | English CONTENTS |
8 | FOREWORD |
10 | 1 Scope 2 Normative references |
11 | 3 Terms, definitions and abbreviated terms 3.1 Terms and definitions |
12 | 3.2 Abbreviated terms 4 Apparatus 4.1 Radiation source 4.1.1 Method A – Time domain (pulse distortion) measurement 4.1.2 Method B – Frequency domain measurement 4.1.3 Method C – Overfilled launch modal bandwidth calculated from differential mode delay (OMBc) 4.1.4 For method A and method B Table 1 – Abbreviated terms |
13 | 4.2 Launch system 4.2.1 Overfilled launch (OFL) |
14 | 4.2.2 Restricted mode launch (RML) Figure 1 – Mandrel wrapped mode filter |
15 | 4.2.3 Differential mode delay (DMD) launch 4.3 Detection system 4.4 Recording system 4.5 Computational equipment 4.6 Overall system performance |
16 | 5 Sampling and specimens 5.1 Test sample 5.2 Reference sample 5.3 End face preparation 5.4 Test sample packaging 5.5 Test sample positioning |
17 | 6 Procedure 6.1 Method A – Time domain (pulse distortion) measurement 6.1.1 Output pulse measurement 6.1.2 Input pulse measurement method A-1: reference sample from test sample 6.1.3 Input pulse measurement method A-2: periodic reference sample 6.1.4 Input pulse measurement method A-3: direct reference |
18 | 6.2 Method B – Frequency domain measurement 6.2.1 Output frequency response 6.2.2 Method B-1: Reference length from test specimen 6.2.3 Method B-2: Reference length from similar fibre 6.2.4 Method B-3: Reference from direct coupling |
19 | 6.3 Method C – Overfilled launch modal bandwidth calculated from differential mode delay (OMBc) Table 2 – DMD weights for calculating overfilled modal bandwidth (OMBc) from DMD data for 850 nm only |
20 | 7 Calculations or interpretation of results 7.1 Bandwidth (−3 dB), f3 dB 7.2 Calculations for optional reporting methods 8 Length normalization 9 Results 9.1 Information to be provided with each measurement |
21 | 9.2 Information available upon request 10 Specification information |
22 | Annex A (normative) Intramodal dispersion factor and the normalized intermodal dispersion limit A.1 Intramodal dispersion factor, IDF Table A.1 – Highest expected dispersion for commercially available A1 fibres |
23 | A.2 Normalized intermodal dispersion limit, NIDL A.3 Derivation of the IDF |
25 | Annex B (normative) Fibre transfer function, H(f), power spectrum, |H(f)|, and f3 dB B.1 Fibre transfer function B.1.1 Method A – Time domain (pulse distortion) measurement B.1.2 Method B – Frequency-domain measurement |
26 | B.2 Power spectrum B.2.1 Method A – Time domain (pulse distortion) measurement B.2.2 Method B – Frequency-domain measurement B.2.3 Bandwidth (−3 dB), f3 dB |
27 | Annex C (normative)Calculations for other reporting methods C.1 Fibre impulse response, h(t) C.2 RMS impulse response, exact method |
28 | C.3 RMS impulse response, difference of squares approximation |
29 | Annex D (normative) Mode scrambler requirements for overfilled launching conditions to multimode fibres D.1 General D.2 Apparatus D.2.1 Light source D.2.2 Mode scrambler |
30 | D.2.3 Cladding mode strippers Figure D.1 – Two examples of optical fibre scramblers |
31 | D.3 Sampling and specimens D.4 Procedure D.4.1 Qualification of mode scrambler |
32 | D.4.2 Alignment of test fibre in mode scrambler output D.4.3 Measurement test D.5 Calculations or interpretation of results |
33 | D.6 Results D.6.1 Information to be provided with each measurement D.6.2 Information available upon request |
34 | Bibliography |