1、TIA TELECOMMUNICATIONS SYSTEMS BULLETIN ITM-3 Mode Power Distribution and Mode Transfer Function Measurement TSB-62-3 Reaffirmed August 15,2002 OAUGUST 1995 TELECOMMUNICATIONS INDUSTRY ASSOCIATION The Teleconmiunications Industry Association represents the conmiunications sector of NOTICE TIA Engine
2、ering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between manufacturers and purchasers, facilitating interchangeability and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper pro
3、duct for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of TIA from manufacturing or selling products not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude th
4、eir voluntary use by those other than TIA members, whether the standard is to be used either domestically or internationally. Standards, Publications and Bulletins are adopted by TIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, TIA does not assum
5、e any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard, Publication, or Bulletin. Technical Bulletins are distinguished from TIA Standards or Documents, in that they contain a compilation of engineering data or information useful to the techn
6、ical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to preclude or discourage other approaches that similarly represent good engineering practice, or that may be acceptable to, or have been accepted by,
7、 appropriate bodies. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in future revisions of this Bulletin are encouraged to do so. It is the intention of the formulating committee to review this document every five years, but it
8、 maybe revised and updated at any time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. (From Project No. 3-3230, formulated under the cognizance of the TIA FO-6.6 Subcommittee on Optical Fibers.) This Document was reaffir
9、med by the Telecommunications Industry Association on August 15,2002. Published by OTELECOMMUNICATIONS INDUSTRY ASSOCIATION 1995 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 U.S.A. PRICE: Please refer to current Catalog of TIA TELECOMMUNICATIONS INDUSTRY ASSOCIATION
10、STANDARDS AND ENGINEERING PUBLICATIONS or call Global Engineering Documents, USA and Canada (1 -800-854-7 179) International (303-397-7956) or search online at http:/www.tiaonline.org/standards/search-n-order .ch All rights reserved Printed in U.S.A. NOTICE OF DISCLAIMER AND LIMITATION OF LIABILITY
11、The document to which this Notice is affixed has been prepared by one or more Engineering Committees of the Telecommunications Industry Association (“TIA”). TIA is not the author of the document contents, but publishes and claims copyright to the document pursuant to licenses and permission granted
12、by the authors of the contents. TIA Engineering Committees are expected to conduct their affairs in accordance with the TIA Engineering Manual (“Manual”), the current and predecessor versions of which are available at http:/www.tiaonline.orZr/standards/sfZr/engineering manual.ch. TIAS function is to
13、 administer the process, but not the content, of document preparation in accordance with the Manual and, when appropriate, the policies and procedures of the American National Standards Institute (“ANSI”). THE USE OR PRACTICE OF CONTENTS OF THIS DOCUMENT MAY INVOLVE THE USE OF INTELLECTUAL PROPERTY
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19、G NEGATION OF DAMAGES IS A FUNDAMENTAL ELEMENT OF THE USE OF THE CONTENTS HEREOF, AND THESE CONTENTS WOULD NOT BE PUBLISHED BY TIA WITHOUT SUCH LIMITATIONS. EIA TSBb2-3 95 I 3234600 05625.51 247 IIA/EIA r ELECOMMUNICATIONS SYSTEMS BULLETIN TM-3 Mode Power Distribution and Mode ransfer Function Measu
20、rement TSB62-3 AUGUST 1995 TELECOMMUNICATIONS INDUSTRY ASSOCIATION EIA TSBb2-3 95 E 3234600 0562552 185 NOTICE TIA/EIA Engineering Standards and Publications are designed to serve the public interest through eliminating misunderstandings between mandacturers and purchasers, facilitating interchangea
21、biility and improvement of products, and assisting the purchaser in selecting and obtaining with minimum delay the proper product for his particular need. Existence of such Standards and Publications shall not in any respect preclude any member or nonmember of MIA fiom manufacturing or selling produ
22、cts not conforming to such Standards and Publications, nor shall the existence of such Standards and Publications preclude their voluntary use by those other than TIAIEIA members, whether the standard is to be used either domestically or internationally. Standards, Publications and Bulletins are ado
23、pted by MIA in accordance with the American National Standards Institute (ANSI) patent policy. By such action, TIA/EIA does not assume any liability to any patent owner, nor does it assume any obligation whatever to parties adopting the Standard, Publication or Bulletin. Technical Bulletins are dist
24、inguished fiom iIA/EIA Standards or Interim Standards, in that they contain a compilation of engineering data or information usefiil to the technical community, and represent approaches to good engineering practices that are suggested by the formulating committee. This Bulletin is not intended to pr
25、eclude or discourage other approaches that similarly represent good engineering practice, or that may be acceptable to, or have been accepted by, appropriate bodies. Parties who wish to bring other approaches to the attention of the formulating committee to be considered for inclusion in hture revis
26、ions of this Bulletin are encouraged to do so. It is the intention of the formulating committee to revise and update this Bulletin fiom time to time as may be occasioned by changes in technology, industry practice, or government regulations, or for other appropriate reasons. Published by OTELECOMMUN
27、ICATIONS INDUSTRY ASSOCIATION 1995 Standards and Technology Department 2500 Wilson Boulevard Arlington, VA 22201 PRICE: Please refer to the current Catalog of EIA, JEDEC and TIA STANDARDS and ENGINEERING PUBLICATIONS International (303-397-7956) or call Global Engineering Documents, USA and Canada (
28、1-800-854-7179) Aii rights reserved Printed in U.S.A. . EIA TSBb2-3 95 I 3234600 0562554 T58 I TSB . 62 . 3 ITM-3 Mode power distri bution and mode transfer function measurement Contents Foreword 3 1 Introduction . 5 1.1 Intent . 5 1.2 Scope . 5 1.3 Background . 5 2 Normative references . 6 3Apparat
29、us . 7 3.1 General 7 3.2 Cladding Mode Stripper . 7 4 Sampl ing and specimens 7 5 Procedure 7 5.1 Test Near Field 7 5.2 Reference Near Field 8 6 Calculations or interpretations of results 8 6.1 Nearfield Calculations . 8 6.2 Mode Power Distribution Calculation 9 6.3 Mode Transfer Function Calculatio
30、n . 9 6.4 Curve Fitting and Smoothing 9 ,6.5 MPD and MTF Normal ization . 10 6.6 MPD and MTF Plotting 10 7 Documentation . 11 Annex A (normative) . 12 Annex B (informative) 13 Annex C (informative) 14 1 TSB 62 - 3 This page left blank. 2 . EIA TSB62-3 75 H 3234600 0562556 20 TSB 62 - 3 ITM-3 Mode po
31、wer distri bution and mode transfer function measurement Foreword This Foreword is not part of this TSB. This document comes from TIA Project No. 3230, and was formulated under the cogni zance of TIA F0-2.2/6.6, Joint Subcommittee on Local Area Network Component Character i zat i on. This Informativ
32、e Test Method (ITM) is part of the series of test procedures i ncl uded wi t h TSB - 62. 3 EIA TSB62-3 75 .I 3234600 0562557 767 TSB - 62 - 3 This page left blank. 4 EIA TSBb2-3 95 3234600 0562558 bT3 TSB - 62 - 3 1 Introduction 1.1 Intent This Informative Test Method (ITM) describes a method to mea
33、sure the Mode Power Distribution (MPD) present in a multimode optical fiber. This fiber may be an integral part of a fiber optic component such as a switch, coupler or cable. This method is applicable to the measurement of the MPD in optical fibers and components, fiber optic systems, or fiber optic
34、 cable plants. This method also may be used to characterize the MPD launched into an optical fiber by a fiber optic source. In addition, this procedure may be used to measure the mode transfer function of a passive fiber optic component. 1.2 scope This method is only applicable to class Ia multimode
35、, graded index optical fibers with profile parameter, g, approximately equal to 2. The fibers may be part of a fiber optic component such as an optical transmitter, switch, coupler or cable and may be within an installed fiber optic system or fiber optic cable plant. 1.3 Background This method is us
36、ed to characterize the distribution of optical power among the modes of a multimode optical fiber. This method is used to study mode mixing and mode stripping effects of optical fibers and other components. This method is al so used to characterize the output (1 aunch) conditions of opt i cal source
37、s. 5 EIA TSBb2-3 95 m 3234600 0562557 53T TSB - 62 - 3 4 2 Normative references Test requirements may include, but are not limited to, the most recent edition of the fol 1 owing references : TSB-62 Informative test methods for fiber-optic fibers, cab7es. opto-e7ectronic sources and detectors, sensor
38、s, connecting and tenninat ing devices, and other fiber -optic carponents . FOTP-43 (TIA/EIA-455-43A) , Output Near-Fie7d Radiation Pattern Measurevnent of Opt ica 7 Fibers. FOTP - 57 (TIA/EIA- 455 - 57B) , Opt ica 7 Fiber End Preparation and Examinat ion. FOTP-58 (TIA/EIA-455-58A). Core Diameter Ma
39、surevnent of Graded-Index Optica 7 Fibers 3 Apparatus 3.1 General The apparatus (including the 1 ight source for reference measurements) shall be as specified in FOTP-43. In addition, the light source used for reference measurements shall have a full width half maximum spectral width between 5 nm an
40、d 200 nm. and shall have a uniformity over the surface area of the input fiber no worse than +/- 10 percent. 3.2 Cladding Mode Stripper Cladding mode power shall be removed from the test specimen. Under some circumstances, the fiber coating will perform this function: otherwise, methods or devices t
41、hat extract cladding mode power shall be employed at the input and output ends of the test specimen. -6 TSB 62 - 3 4 Sampl ing and specimens The test specimen shall consist of an optical fiber or a fiber-optic component (including fiber optic sources) constructed with optical fiber pigtails. The min
42、imum fiber or pigtail length shall be 1 m. 5 Procedure 5.1 Test Near Field Prepare the fiber ends of the test specimen to assure flat endfaces perpendicular to the fiber axis (refer to FOTP-57). Measure the output near-field radiation pattern of the test specimen or the optical fiber pigtail of the
43、test specimen in accordance with FOTP -43. The input 1 i ght 1 aunch condi ti ons shall be a uni form overfill as described in clause 3.1 for passive components and shall be “as generated“ for active components. The effective step size of the nearfield pattern measurement shall be no greater than 1
44、pm. 5.2 Reference Near Fi el d Prepare the fiber ends of the reference length to assure flat endfaces perpendicular to the fiber axis (refer to FOTP-57). Measure the output near- field radiation pattern of a short reference length (1.0 +/- 0.25 m) of optical fiber with a refractive index profile sim
45、ilar to that of the test specimen fiber in accordance with FOTP-43. This may be accomplished by performing a cutback of the test specimen or by replacing the test specimen with a short optical fiber with the appropriate refractive index profile. The input light launch conditions shall be a uniform o
46、verfill as described in clause 3. The effective step size of the nearfield pattern measurement shall be the same as used in 5.1. 7 EIA TSBb2-3 95 3234600 05b25bL 198 TSB - 62 - 3 6 Cal cul ations or interpretations of results 6.1 Nearfield Calculations Determine the core diameter of the reference le
47、ngth using FOTP-58. Determine the center point of both the test specimen and reference length data patterns. NOTE 1 - A recommended method for determining the center point of equally spaced data is as follows. Determine the number of data points contained between the 2.5% levels of the measured data
48、 set. If the number of data points is odd, the center point is the median point. If the number of data points is even, the center point is the mean of the two median data points. NOTE 2 - A more general method of determining the center point of equally spaced data is to determine the “center of mass
49、“ of the data set. The center point is the point at which the magnitude of the data set sum is one-half the magnitude of the total data set sum. Average each data set about the center point and calculate the offset of each scan position from its respective center point. For both the test specimen data set and the reference length data set, convert each scan position to relative mode number (relative composite mode number) using the relation: m = (r/aI2 where m is the relative mode number, r is the offset of each scan position from its center po
