IS/IEC 60793-1-34 : 2006 Hkkjrh; ekud çdkf'kd rarq Hkkx 1 ekiu fofèk;k¡ vkSj ijh{k.k çfØ;k,¡ vuqHkkx 34 rarq dyZ Indian Standard OPTICAL FIBRES PART 1 MEASUREMENT METHODS AND TEST PROCEDURES Section 34 Fibre Curl ICS 33.180.10 © BIS 2013 B U R E A U O F I N D I A N S T A N D A R D S MANAK BHAVAN, 9 BAHADUR SHAH ZAFAR MARG NEW DELHI 110002 May 2013 Price Group 7 IS/IEC 60793-1-34 : 2006 Fibre Optics, Fibres, Cables and Devices Sectional Committee, LITD 11 NATIONAL FOREWORD This Indian Standard (Part 1/Sec 34) which is identical with IEC 60793-1-34 : 2006 ‘Optical fibres — Part 1-34: Measurement methods and test procedures — Fibre curl’ issued by the International Electrotechnical Commission (IEC) was adopted by the Bureau of Indian Standards on the recommendation of the Fibre Optics, Fibres, Cables and Devices Sectional Committee and approval of the Electronics and Information Technology Division Council. The text of IEC Standard has been approved as suitable for publication as an Indian Standard without deviations. Certain conventions are, however, not identical to those used in Indian Standards. Attention is particularly drawn to the following: a) Wherever the words ‘International Standard’ appear referring to this standard, they should be read as ‘Indian Standard’. b) Comma (,) has been used as a decimal marker while in Indian Standards, the current practice is to use a point (.) as the decimal marker. In this adopted standard, reference appears to certain International Standards for which Indian Standards also exist. The corresponding Indian Standards which are to be substituted in their respective places are listed below along with their degree of equivalence for the editions indicated: International Standard Corresponding Indian Standard Degree of Equivalence IEC 60793-1-1 : 2008 Optical fibers IEC 60793-1-1 : 2008 Optical fibers: Identical — Part 1-1: Measurement method Part 1 Measurement method and test and test procedures — General and procedures, Section 1 General and guidance guidance IEC 60793-1-20 : 2001 Optical fibres IS/IEC 60793-1-20 : 2001 Optical do — Part 1-20: Measurement method fibres: Part 1 Measurement and test procedures — Fibre methods and test procedures, geometry Section 20 Fibre geometry IEC 60793-1-21 : 2001 Optical fibres IS/IEC 60793-1-21:2001 Optical do — Part 1-21: Measurement methods fibres: Part 1 Measurement and test procedures — Coating methods and test procedures, geometry Section 21 Coating geometry IEC 60793-1-22 : 2001 Optical fibres IS/IEC 60793-1-22 : 2001 Optical do — Part 1-22: Measurement methods fibres: Part 1 Measurement methods and test procedures — Length and test procedures, Section 22 measurement Length measurement IEC 60793-1-30 : 2010 Optical fibres IS/IEC 60793-1-30 : 2010 Optical do — Part 1-30: Measurement methods fibres: Part 1 Measurement methods and test procedures — Fibre proof and test procedures, Section 30 Fibre test proof test IEC 60793-1-31: 2010 Optical fibres IS/IEC 60793-1-31 : 2010 Optical do — Part 1-31 : Measurement methods fibres: Part 1 Measurement methods and test procedures — Tensile and test procedures, Section 31 strength Tensile strength IEC 60793-1-32: 2010 Optical fibres IS/IEC 60793-1-32 : 2010 Optical do — Part 1-32 : Measurement methods fibres: Part 1 Measurement methods and test procedures — Coating and test procedures, Section 32 strippability Coating strippability i IS/IEC 60793-1-34 : 2006 International Standard Corresponding Indian Standard Degree of Equivalence IEC 60793-1-33 : 2001 Optical fibres IS/IEC 60793-1-33 : 2001 Optical Identical — Part 1-33: Measurement methods fibres: Part 1 Measurement methods and test procedures — Stress and test procedures, Section 33 corrosion susceptibility Stress corrosion susceptibility IEC 60793-1-40 : 2001 Optical fibres IS/IEC 60793-1-40 : 2001 Optical do — Part 1-40: Measurement methods fibres: Part 1 Measurement methods and test procedures — Attenuation and test procedures, Section 40 Attenuation IEC 60793-1-41 : 2010 Optical fibres IS/IEC 60793-1-41 : 2010 Optical do — Part 1-41: Measurement methods fibres: Part 1 Measurement methods and test procedures — Bandwidth and test procedures, Section 41 Bandwidth IEC 60793-1-42 : 2007 Optical fibres IS/IEC 60793-1-42 : 2007 Optical do — Part 1-42: Measurement methods fibres: Part 1 Measurement methods and test procedures — Chromatic and test procedures, Section 42 dispersion Chromatic dispersion IEC 60793-1-43 : 2001 Optical fibres IS/IEC 60793-1-43 : 2001 Optical do — Part 1-43: Measurement methods fibres: Part 1 Measurement methods and test procedures — Numerical and test procedures, Section 43 aperture Numerical aperture IEC 60793-1-44 : 2011 Optical fibres IS/IEC 60793-1-44 : 2011 Optical do — Part 1-44: Measurement methods fibres: Part 1 Measurement methods and test procedures — Cut-off and test procedures, Section 44 Cut- wavelength off wavelength IEC 60793-1-45 : 2001 Optical fibres IS/IEC 60793-1-45 : 2001 Optical do — Part 1-45: Measurement methods fibres: Part 1 Measurement methods and test procedures — Mode field and test procedures, Section 45 diameter Mode field diameter IEC 60793-1-46 : 2001 Optical fibres IS/IEC 60793-1-46 : 2001 Optical do — Part 1-46: Measurement methods fibres: Part 1 Measurement methods and test procedures — Monitoring of and test procedures, Section 46 changes in optical transmittance Monitoring of changes in optical transmittance IEC 60793-1-47 : 2009 Optical fibres IS/IEC 60793-1-47 : 2009 Optical do — Part 1-47: Measurement methods fibres: Part 1 Measurement methods and test procedures — Macrobending and test procedures, Section 47 loss Macrobending loss IEC 60793-1-48 : 2007 Optical fibres IS/IEC 60793-1-48 : 2007 Optical do — Part 1-48: Measurement methods fibres: Part 1 Measurement methods and test procedures — Polarization and test procedures, Section 48 mode dispersion Polarization mode dispersion IEC 60793-1-49 : 2006 Optical fibres IS/IEC 60793-1-49 : 2006 Optical do — Part 1-49: Measurement methods fibres: Part 1 Measurement methods and test procedures — Differential and test procedures, Section 49 mode delay Differential mode delay IEC 60793-1-50 : 2001 Optical fibres IS/IEC 60793-1-50 : 2001 Optical do — Part 1-50: Measurement methods fibres: Part 1 Measurement and test procedures — Damp heat methods and test procedures, (steady state) Section 50 Damp heat (steady state) IEC 60793-1-51 : 2001 Optical fibres IS/IEC 60793 -1-51 : 2001 Optical do — Part 1-51: Measurement methods fibres: Part 1 Measurement methods and test procedures — Dry heat and test procedures, Section 51 Dry heat ii IS/IEC 60793-1-34 : 2006 International Standard Corresponding Indian Standard Degree of Equivalence IEC 60793-1-52 : 2001 Optical fibres IS/IEC 60793-1-52 : 2001 Optical Identical — Part 1-52: Measurement methods fibres: Part 1 Measurement methods and test procedures — Change of and test procedures, Section 52 temperature Change of temperature IEC 60793-1-53 : 2001 Optical fibres IS/IEC 60793-1-53 : 2001 Optical do — Part 1-53: Measurement methods fibres: Part 1 Measurement and test procedures — Water methods and test procedures, immersion Section 53 Water immersion IEC 60793-1-54 : 2003 Optical fibres IS/IEC 60793-1-54 : 2003 Optical do — Part 1-54: Measurement methods fibres: Part 1 Measurement methods and test procedures — Gamma and test procedures, Section 54 irradiation Gamma irradiation IEC 60793-2 : 2007 Optical fibres — IS/IEC 60793-2 : 2007 Optical fibres: do Part 2: Product specifications — Part 2 Product specifications — General General Only the English language text has been retained while adopting it in this Indian Standard and as such the page numbers given here are not the same as in the IEC Publication. For the purpose of deciding whether a particular requirement of this standard is complied with, the final value, observed or calculated, expressing the result of a test or analysis, shall be rounded off in accordance with IS 2 : 1960 ‘Rules for rounding off numerical values (revised)’. The number of significant places retained in the rounded off value should be the same as that of the specified value in this standard. iii IISS//IIEECC 6600779933--11--3344 :: 22000066 Indian Standard OPTICAL FIBRES PART 1 MEASUREMENT METH ODS AND TEST PROCEDURES Section 34 Fibre Curl 1 Scope This part of IEC 60793 establishes uniform requirements for the mechanical characteristic: fibre curl or latent curvature, in uncoated optical fibres. Fibre curl has been identified as an important parameter for minimizing the splice loss of optical fibres when using passive alignment fusion splicers or active alignment mass fusion splicers. Two methods are recognized for the measurement of fibre curl, in uncoated optical fibres: • method A: side view microscopy; • method B: laser beam scattering. Both methods measure the radius of curvature of an uncoated fibre by determining the amount of deflection that occurs as an unsupported fibre end is rotated about the fibre's axis. Method A uses visual or digital video methods to determine the deflection of the fibre while method B uses a line sensor to measure the maximum deflection of one laser beam relative to a reference laser beam. By measuring the deflection behaviour of the fibre as it is rotated about its axis and understanding the geometry of the measuring device, the fibre's radius of curvature can be calculated from simple circular models, the derivation of which are given in Annex C. Both methods are applicable to types A1, A2, A3 and B optical fibres as described in the IEC 60793 series. Method A is the reference test method, used to resolve disputes. 2 Normative references The following referenced documents are indispensable for the application of this document. For dated references, only the edition cited applies. For undated references, the latest edition of the referenced document (including any amendments) applies. IEC 60793 (all parts), Optical fibres 3 Apparatus 3.1 Principle An uncoated fibre end is mounted in a rotatable fixture so that the end extends freely into space by an overhang distance which will depend on the measurement device. The overhang distance is typically 10 mm to 20 mm. If the measurement device is designed with overhang distances greater than this, care must be taken to avoid excessive degradation due to effects of vibration and gravity. The fibre is rotated and the deviations in the position of the overhang point relative to a reference position are measured to obtain the fibre’s radius of curvature, r . c 11 IS/IEC 60793-1-34 : 2006 Details pertaining to the two methods are given in the relevant Annex A or B. Common apparatus requirements are given below. 3.2 Fibre holding fixture Provide a fixture that holds the fibre on a constant axis at the holding position and allows the fibre to be rotated through 360°. The fixture may be a v-groove holder such as a vacuum chuck or a fibre ferrule. If a ferrule is used, take care to ensure that the inside diameter is sized closely enough to the fibre diameter to minimize variability in the deflection measurements. 3.3 Fibre rotator Provide a device to grip and rotate the fibre through 360°. The device may be manually operated, or may be driven by a rotational device such as a stepper motor. 3.4 Deflection measurement device Provide a deflection measurement device according to either Annex A or Annex B. 3.5 Computer (optional) A computer may be used to provide motion control, data collection and computation. 4 Sample preparation Use an uncabled fibre of appropriate length for the instrument design. Remove enough coating from one end to allow mounting in the fibre fixture with the necessary overhang. The fibre should not extend much past the measuring device’s required overhang distance since excessive lengths can cause degradation as discussed in Clause 3. 5 Procedure Details for each method are given in Annexes A and B. Common procedures are described below. 5.1 Mounting of the fibre Mount the fibre in the holding fixture so that the stripped end extends into free space with sufficient length to extend up to or beyond the overhang distance. Typical overhang distances range between 10 mm and 20 mm. Attach the other end of the fibre to the fibre rotator. If the overhang distance is excessive, or the stripped fibre is substantially longer than the required overhang distance, then the measurement may be degraded. 5.2 Rotation Follow the procedure of Annex A or Annex B. 5.3 Calculation Complete the detailed calculation of the fibre curl, r , using Annex A or Annex B. c NOTE Though the intermediate parameters used in the calculations are typically scaled in micrometres, the radius of curvature, r , is typically re-scaled in units of metres. c 2 IS/IEC 60793-1-34 : 2006 6 Results 6.1 The following information should be reported for each test: • date of the test; • fibre identification; • fibre radius of curvature. 6.2 The following information should be available for each test: • method used to determine curl; • description of the equipment; • calibration data. 7 Specification information The detail specification shall specify the following: • information to be reported; • any deviations to the procedure that apply; • failure or acceptance criteria. 3 IS/IEC 60793-1-34 : 2006 Annex A (normative) Fibre curl by side view microscopy A.1 Principle This procedure measures the radius of curvature of an uncoated fibre by determining the amount of deflection that occurs as an unsupported fibre end is rotated about the fibre's axis. By knowing the amplitude of the deflection of the fibre and the overhang distance from the fibre fixture to the measurement point, the fibre's radius of curvature can be calculated from a simple circular model, the derivation of which is given in Clause C.1. Schematic diagrams of typical test set-ups for these techniques are shown in Figures A.1, A.2 and A.3. A.2 Apparatus A.2.1 Deflection measurement device Provide a device to measure the fibre deflection as it is rotated through 360°. Such a device may consist of a viewing microscope or an optical measuring instrument such as a laser micrometer. If a viewing microscope is used, provide means to permit accurate measurement of fibre deflection, such as a filar eyepiece or a digital image analysis system. A.2.2 Video camera and monitor A video camera and monitor may be used to enhance the viewing system for manual or automated operation. A.2.3 Digital image analysis system (optional) A digital video analyser may be used to provide more precise location of the deflections than might be obtained by a filar eyepiece. Such a system might include an analogue or digital video camera, a frame grabber and associated software for the purpose of locating the fibre’s position at the overhang distance as the fibre is rotated. A.3 Test procedure A.3.1 General Two techniques are provided for obtaining the deflection, δ. The first is an extrema technique f that is limited by the precision with which the extremes of the deflection can be determined. The second is a Fourier fitting method. 4