BS EN 61300-3-40-1998 Fibre optic interconnecting devices and passive components - Basic test and measurement procedures - Examinations and measurements - Extinction ratio of a polc.pdf

1、BRITISH STANDARD BS EN 61300-3-40:1998 IEC 61300-3-40:1998 Fibre optic interconnecting devices and passive components Basic test and measurement procedures Part 3-40: Examinations and measurements Extinction ratio of a polarization maintaining (pm) fibre pigtailed connector The European Standard EN

2、61300-3-40:1998 has the status of a British Standard ICS 33.180.20BSEN61300-3-40:1998 This British Standard, having been prepared under the directionof the Electrotechnical Sector Board, was published underthe authority of the Standards Board and comes intoeffect on 15 July 1998 BSI 04-1999 ISBN 0 5

3、80 30116 8 National foreword This British Standard is the English language version of EN61300-3-40:1998. It is identical with IEC61300-3-40:1998. The UK participation in its preparation was entrusted by Technical Committee EPL/86, Fibre optics, to Subcommittee EPL/86/2, Interconnecting devices and p

4、assive components, which has the responsibility to: aid enquirers to understand the text; present to the responsible international/European committee any enquiries on the interpretation, or proposals for change, and keep the UK interests informed; monitor related international and European developme

5、nts and promulgate them in the UK. A list of organizations represented on this subcommittee can be obtained on request to its secretary. From 1 January 1997, all IEC publications have the number 60000 added to the old number. For instance, IEC27-1 has been renumbered as IEC60027-1. For a period of t

6、ime during the change over from one numbering system to the other, publications may contain identifiers from both systems. Cross-references Attention is drawn to the fact that CEN and CENELEC Standards normally include an annex which lists normative references to international publications with thei

7、r corresponding European publications. The British Standards which implement these international or European publications may be found in the BSI Standards Catalogue under the section entitled “International Standards Correspondence Index”, or by using the “Find” facility of the BSI Standards Electr

8、onic Catalogue. A British Standard does not purport to include all the necessary provisions of a contract. Users of British Standards are responsible for their correct application. Compliance with a British Standard does not of itself confer immunity from legal obligations. Summary of pages This doc

9、ument comprises a front cover, an inside front cover, pages i and ii, theEN title page, pages 2 to 5 and a back cover. This standard has been updated (see copyright date) and may have had amendments incorporated. This will be indicated in the amendment table on the inside front cover. Amendments iss

10、ued since publication Amd. No. Date CommentsBSEN61300-3-40:1998 BSI 04-1999 i Contents Page National foreword Inside front cover Foreword 2 Text of EN 61300-3-40 3ii blankEUROPEAN STANDARD NORME EUROPENNE EUROPISCHE NORM EN 61300-3-40 April 1998 ICS 33.180.20 English version Fibre optic interconnect

11、ing devices and passive components Basic test and measurement procedures Part 3-40: Examinations and measurements Extinction ratio of a polarization maintaining (pm) fibre pigtailed connector (IEC 61300-3-40:1998) Dispositifs dinterconnexion et composants passifs fibres optiques Mthodes fondamentale

12、s dessais et de mesures Partie 3-40: Examens et mesures Rapport dextinction dun connecteur fibre amorce maintenant la polarisation (pm) (CEI 61300-3-40:1998) Lichtwellenleiter Verbindungselemente und passive Bauteile Grundlegende Prf und Meverfahren Teil 3-40: Untersuchungen und Messungen Messung de

13、r Verminderung des Extinktionsverhltnisses eines Steckverbinders mit einer polarisationserhaltenden (PM) Anschlufaser (CEI 61300-3-40:1998) This European Standard was approved by CENELEC on 1998-04-01. CENELEC members are bound to comply with the CEN/CENELEC Internal Regulations which stipulate the

14、conditions for giving this European Standard the status of a national standard without any alteration. Up-to-date lists and bibliographical references concerning such national standards may be obtained on application to the Central Secretariat or to any CENELEC member. This European Standard exists

15、in three official versions (English, French, German). A version in any other language made by translation under the responsibility of a CENELEC member into its own language and notified to the Central Secretariat has the same status as the official versions. CENELEC members are the national electrot

16、echnical committees of Austria, Belgium, Czech Republic, Denmark, Finland, France, Germany, Greece, Iceland, Ireland, Italy, Luxembourg, Netherlands, Norway, Portugal, Spain, Sweden, Switzerland and United Kingdom. CENELEC European Committee for Electrotechnical Standardization Comit Europen de Norm

17、alisation Electrotechnique Europisches Komitee fr Elektrotechnische Normung Central Secretariat: rue de Stassart 35, B-1050 Brussels 1998 CENELEC All rights of exploitation in any form and by any means reserved worldwide for CENELEC members. Ref. No. EN 61300-3-40:1998 EEN61300-3-40:1998 BSI 04-1999

18、 2 Foreword The text of document 86B/1040/FDIS, future edition1 of IEC 61300-3-40, prepared by SC 86B, Fibre optic interconnecting devices and passive components, of IEC TC 86, Fibre optics, was submitted to the IEC-CENELEC parallel vote and was approved by CENELEC as EN 61 300-3-40 on1998-04-01. Th

19、e following dates were fixed: Endorsement notice The text of the International Standard IEC61300-3-40:1998 was approved by CENELEC as a European Standard without any modification. Contents Page Foreword 2 1 General 3 1.1 Scope 3 1.2 General description 3 2 Apparatus 3 3 Procedure 4 4 Details to be s

20、pecified 4 Figure 1 Measurement set-up: reference measurement 5 Figure 2 Measurement set-up 5 latest date by which the EN has to be implemented at national level by publication of an identical national standard or by endorsement (dop) 1999-01-01 latest date by which the national standards conflictin

21、g with the EN have to be withdrawn (dow) 2001-01-01EN61300-3-40:1998 BSI 04-1999 3 1 General 1.1 Scope and object This part of IEC 61300 describes the procedure to measure the ability of an optical fibre connector to maintain a given extinction ratio across the connection in pm fibre. In this test w

22、e limit the measurement to the most common case of nearly linearly polarized light propagating in pm fibre. The term “extinction ratio” used here refers to the proportion of light propagating in the two orthogonal polarization axes of the fibre and is more properly defined as “polarization crosstalk

23、”. “Extinction ratio” is the commonly used term. This procedure has been designed for use with dedicated equipment in a manufacturing environment and thus incorporates a rather elaborate test configuration. It should be noted that other more direct test configurations can be used in suitably equippe

24、d optical laboratories. These may be the subject of additional test procedures in the future. It should be noted that this test procedure is not designed for long term continuous testing; drift of polarization alignment can occur particularly in the single-mode fibre. Hence, repeated rather than con

25、tinuous measurement is required for long term testing of components. 1.2 General description Polarization maintaining fibre has the ability to maintain the proportions of light polarized parallel to the two axes of symmetry of the fibre even when there is moderate bending of the fibre. A connector s

26、ystem intended for use with pm fibre should accordingly create minimum disturbance to this proportioning of the propagating light. In the case of light highly polarized along one axis of the fibre the ratio of these two portions of the light is called the extinction ratio and is usually expressed in

27、 decibels. A connector can degrade the extinction ratio in two ways. Firstly, the connector can have non-ideal keying so that the two ends of the fibres being joined are not perfectly aligned with respect to their axes of birefringence. Secondly, the connector-to-fibre fixing mechanism can cause dis

28、tortions or non-symmetrical stresses to the fibre which result in extinction ratio degradation. This test is intended to measure the extinction ratio for connectors in which the former mechanism is the dominant source of extinction ratio degradation. The degree to which the latter mechanism affects

29、the extinction ratio must be measured during the pigtailing process and hence would be applicable to field mountable pm fibre connectors or to the assembly process at the connector pigtail manufacturers location. 2 Apparatus The apparatus and arrangement necessary to make this measurement is shown i

30、nFigure 1. It consists of: an optical source, S of known characteristics (wavelength, spectral width, etc.) and a compatible detector, D. The accuracy of this test will be affected by interference effects among elements of the test apparatus and the device under test and therefore care should be tak

31、en on the coherence of the light source. This test procedure requires that the light source has a low degree of coherence since use of a highly coherent source, such as a DFB laser, can produce false measurement results. A Fabry-Perot laser with three or more primary longitudinal modes of oscillatio

32、n is suitable for this test. Ideally, an LED is the preferred source if the spectral characteristics of the test component and the dynamic range of the measurement required can accommodate this type of source. Specifically, the source must launch enough power into the fibre so that the minimum signa

33、l measured through the test component is at least 3 dB higher than the noise floor of the detector; an in-line polarization assembly of polarizer, quarter-wave retardation plate and half-wave retardation plate in an expanded beam formed by two lenses L1 and L2. The polarizer linearly polarizes the l

34、ight to a high extinction ratio; the quarter-wave plate converts the state of polarization (SOP) from linear to elliptical or circular; and the half-wave plate rotates the direction of polarized light. With this combination of elements, it can be seen that every possible SOP can be produced; a tempo

35、rary joint, TJ; a reference pm fibre pigtail. This could be a pigtail of the type to be measured which has previously been determined to be accurate (tolerances to be specified in relevant specification) dimensionally (keying, core alignment, etc.); an analyzer, A, to determine the extinction ratio

36、of light. The polarization optics described in this test procedure is based on bulk optical elements; i.e.waveplates and a polarizer. It is also permissible to assemble the polarization optics by other means such as fibre loop polarization elements.EN61300-3-40:1998 4 BSI 04-1999 Comment on apparatu

37、s: the purpose of the section of sm fibre at the output of the polarization optics is to facilitate an optical joint to a variety of reference pm fibre pigtails. It is also permitted to eliminate this section of sm fibre and replace it with a direct coupling of the polarization optics to the referen

38、ce pm pigtail. Furthermore, since the presence of cladding modes will degrade the accuracy of measurement, it is assumed that the fibre jacket for all single-mode and pm fibre sections acts as a cladding mode stripper. 3 Procedure The first part of this procedure sets a high degree of linear polariz

39、ation aligned to a fibre polarization axis at the output of the reference pigtail connector. During this procedure care should be taken not to move the singlemode fibre sections of the arrangement. With the measurement arrangement set up as inFigure 1: a) with arbitrary settings of the quarter and h

40、alf-wave retardation plates and the analyzer adjust the polarizer to get a maximum measurement at the detector; b) adjust analyzer, A, to get a minimum measurement at the detector; c) adjust quarter-wave plate to get minimum measurement at the detector; d) adjust half-wave plate to get minimum measu

41、rement at the detector; e) repeat steps b), c) and d) until the lowest measurement attainable is achieved (two or three iterations). Record this measurement as DMIN i(dBm). At this point of the procedure a check on the polarization alignment can be made by inducing gentle bending and twisting motion

42、 in the test pigtail while monitoring the power meter. Power fluctuations of greater than 1 dB indicate that the polarization alignments to the principal axes are not correct and realignment is necessary; f) adjust the analyzer to obtain a maximum reading at the detector. Record this reading as DMAX

43、 i(dBm). The initial extinction ratio of the light, ER i , is given by DMAX i DMIN i(dB). Since this value is a limit to the measurement range of the system, it is normal to require that this value be10 dB greater than the maximum expected measurement of the extinction ratio made on the test pigtail

44、. The next part of this procedure measures the degree of linear polarization as an extinction ratio after the connection to the pigtail to be evaluated. A comparison to the initial extinction ratio will give the degradation in extinction ratio. Taking care not to disturb the singlemode fibre parts o

45、f the arrangement, connect the pigtail to be tested to the reference connector and mate the fibre end (properly cleaved) or the connector (in the case of a patchcord) to the analyzer as shown inFigure 2. g) adjust the analyzer to obtain a minimum reading at the detector. Record this reading as DMIN

46、f(dBm). h) adjust the analyzer to obtain a maximum reading at the detector. Record this reading as DMAX f(dBm). The final extinction ratio of the light, ER f , is given by DMAX f DMIN f(dB). The change in the extinction ratio, ER i ER f , gives the extinction ratio caused by the polarization maintai

47、ning fibre pigtail, in combination with the reference connector. Since this test will give results dependent on the particular alignment of the keying, repeated measurements will normally be made to determine the performance of a connector pigtail. 4 Details to be specified The following details, as

48、 applicable, shall be specified in the relevant specification. source S including spectral width or coherence length, stability and peak wavelength; relevant performance details of the in-line polarization assembly; accuracy of alignment of the axes of the pm fibre to the key of the reference plug a

49、nd other requirements for the reference plug; detector spectral response; detector linearity; details of the temporary joint; cladding mode stripper requirements; techniques required to ensure repeatable measurements; performance requirements: minimum value of ER i ; minimum value of ER f .EN61300-3-40:1998 BSI 04-1999 5 Figure 1 Measurement set-up: reference measurement Figure 2 Measurement set-upBS EN 61300-3-40:1998 IEC 61300-3-40:1998 BSI 389 Chiswick High Road London W4 4AL BSIBritishStand