GB/T 15972.49-2021Specifications for optical fibre test methods - Part 49: Measurement methods and test procedures for transmission characteristics - Differential mode delay (English PDF)

Foreword

GB/T 15972 "Specifications for Optical Fiber Test Methods" consists of several parts, and its structure is as follows.

---Part 10.General principles of measurement methods and test procedures;

---Part 20~Part 29.Measurement methods and test procedures of dimensional parameters;

---Part 30~Part 39.Measurement methods and test procedures of mechanical properties;

---Part 40~Part 49.Measurement methods and test procedures for transmission characteristics;

---Part 50~Part 59.Environmental performance measurement methods and test procedures.

Among them, GB/T 15972.4x consists of the following parts.

---Part 40.Measurement methods and test procedures for transmission characteristics attenuation;

---Part 41.Measurement methods of transmission characteristics and test procedure bandwidth;

---Part 42.Measurement methods and test procedures for transmission characteristics. Wavelength dispersion;

---Part 43.Measurement methods of transmission characteristics and test procedures Numerical aperture;

---Part 44.Measurement methods of transmission characteristics and test procedures cut-off wavelength;

---Part 45.Measurement methods and test procedures for transmission characteristics; Mode field diameter;

---Part 46.Measurement methods of transmission characteristics and test procedures for light transmittance changes;

---Part 47.Measurement methods and test procedures for transmission characteristics, macrobending loss;

---Part 48.Measurement methods and test procedures for transmission characteristics Polarization mode dispersion;

---Part 49.Differential modulus delay for measurement methods and test procedures of transmission characteristics.

This part is part 49 of GB/T 15972.

This part was drafted in accordance with the rules given in GB/T 1.1-2009.

This part replaces GB/T 15972.49-2008 "Specification for optical fiber test methods-Part 49.Measurement of transmission characteristics and optical characteristics

Methods and Test Procedures Differential Modulus Delay. Compared with GB/T 15972.49-2008, the main technical changes in this part are as follows.

---Added some normative reference documents (see Chapter 2);

---Added the three terms of differential modulus delay, quadrant and 25% full width (see Chapter 3, Chapter 3 of the.2008 edition);

---Added abbreviations (see Chapter 4);

---Added an overview of the exportable parameters minEMBc and OMBc (see Chapter 5);

---Added "pulse semiconductor laser or mode-locked fiber laser" as a light source that can meet the requirements (see 6.2,.2008 edition

5.1);

--- Deleted the high-order mode filtering chapter, adjusted the content to the scan pigtail chapter (see 6.3, 5.3.3 of the.2008 edition);

---Added the requirements of EMBc and OMBc for mode correlation in the detection system (see 6.7, 5.4.1 of the.2008 edition);

---Added system performance requirements (see 6.10);

---Added deconvolution and pulse overlap (see 9.2.2, 9.2.3);

---Modified the process of DMD determination (see 9.2.4, 8.1 in.2008 edition);

---Added the calculation and result description of the minimum calculation effective mode bandwidth (see 9.3);

---Added informative Appendix B. Determination of Fiber Optics Center (see Appendix B);

--- Added normative appendix C. mode measurement of the detection system (see appendix C);

---Adjust Appendix B of the.2008 edition to Appendix D of this document (see Appendix D, Appendix B of the.2008 edition);

---Added Appendix E to determine the DMD weight when calculating EMBC (see Appendix E);

---The calculation of EMBC in Appendix F has been added (see Appendix F);

--- Added the structural changes in this part of Appendix G compared with IEC 60793-1-49.2018 (see Appendix G).

This part uses the redrafting method to modify and adopt IEC 60793-1-49.2018 ``Optical Fiber Part 1-49.Measurement Methods and Test Procedures

Differential Modular Delay."

Compared with IEC 60793-1-49.2018, this part has structural adjustments. The specific adjustments are as follows.

--- Due to the addition of Chapter 4 and the change of part of Chapter 1 to Chapter 5, the number of subsequent chapters has been postponed;

--- Chapter 8 and Chapter 9 of International Standards are merged into Chapter 10 of this Part.

The technical differences between this part and IEC 60793-1-49.2018 and the reasons are as follows.

---Regarding normative reference documents, this section has made adjustments with technical differences to adapt to my country's technical conditions and adjustments

It is collectively reflected in Chapter 2 "Normative Reference Documents", and the specific adjustments are as follows.

* Replace IEC 60793-1-22 with GB/T 15972.22 modified to adopt international standards;

* Replace IEC 60793-1-41 with GB/T 15972.41 modified to adopt international standards;

* Added reference to GB/T 14733.12;

* Removed IEC 60793-1-1.2017, IEC 60793-1-45, IEC 60825-1 and IEC 60825-2.

---Added the reference standard in the chapter on terms and definitions;

--- The terms MFD and benchmark test method have been deleted, and the inner limit of the radial scan position, the outer limit of the radial scan position, and the calculated

Three terms of effective mode bandwidth;

---Added a chapter on acronyms;

---Change the description of light source safety in the IEC document from the main text to the note;

--- Modify the injection fiber (launchfibre) in Figure 1 to scan pigtail (probefibre); modify the formula (A.2) in the IEC file

mistake;

--- Split formula (8) into formula (8) and formula (9), and the subsequent formula numbers are extended;

---Revised the title of Table A.1 in Appendix A, and revised "Worst Dispersion" to "Maximum Expected Color of Commercial Type A1 Multimode Fiber

Scattered".

This section has made the following editorial changes.

---In order to be consistent with my country's technical standard system, the standard name of this part is changed to "Optical Fiber Test Method Specification Part 49.Transmission Characteristics

Differential modulus delay of the measurement method and test procedure of the characteristic";

---Adjusted references.

1 Scope

This part of GB/T 15972 describes the test method of optical fiber differential mode delay, and establishes the test equipment, injection conditions, procedures, and calculations.

Uniform requirements for calculation methods and results.

This part is applicable to the measurement of differential mode delay of A1 graded index multimode fiber.

The test methods determined in this section are generally used in indoor environments and are not suitable for operation in the field.

Note. Gigabit Ethernet system uses laser as light source. When this system uses type A1 multimode fiber as the transmission medium, the measurement result of differential mode delay is

To evaluate the bandwidth performance of multimode fiber under this application condition.

2 Normative references

The following documents are indispensable for the application of this document. For dated reference documents, only the dated version applies to this article

Pieces. For undated reference documents, the latest version (including all amendments) is applicable to this document.

GB/T 14733.12 Telecom terminology optical fiber communication [GB/T 14733.12-2008, IEC 60050(731).2008, IDT]

GB/T 15972.22 Optical fiber test method specification Part 22.Dimension parameter measurement method and test procedure length

(GB/T 15972.22-2008, IEC 60793-1-22.2001, MOD)

GB/T 15972.41 Optical fiber test method specification Part 41.Transmission characteristics and optical characteristics measurement methods and test procedures

Wide (GB/T 15972.41-2021, IEC 60793-1-41.2010, MOD)

IEC 61280-1-4 Optical Fiber Communication Subsystem Test Procedure Part 1-4.General Communication Subsystem Light Source Encircled Flux Test Method

(Fibreopticcommunicationsubsystemtestprocedures-Part 1-4.Generalcommunicationsubsys-

tems-Lightsourceencircledfluxmeasurementmethod)

3 Terms and definitions

The following terms and definitions defined in GB/T 14733.12 apply to this document.

3.1

Radial scan position inner limit

RINNER

The inner limit of the radial offset position when the scanning pigtail is scanned radially on the end face of the fiber under test.

3.2

Outer limit of radial scan position

ROUTER

The outer limit of the radial offset position when the scanning pigtail is scanned radially on the end face of the tested fiber.

3.3

Differential mode delay; DMD

Between the fastest and slowest modes excited at all radial offset positions between RINNER and ROUTER (including RINNER and ROUTER)

Estimated difference in optical pulse delay.