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T e l e c o m m u n i c a t i o n
ITU-T
U n
G.6
(11
TELECOMMUNICATION STANDARDIZATION SECTOR OF ITU
SERIES G: TRANSMISSION SYSTEMS AND MEDIA DIGITAL SYSTEMS AND NETWORKS
Transmission Transmission media and optical systems characterist Optical fibre cables
Characteristics of a bending-loss insensitive single-mode optical fibre and cable for the access network
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ITU-T G-SERIES RECOMMENDATIONS TRANSMISSION SYSTEMS AND MEDIA, DIGITAL SYSTEMS AND NETWORKS
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INTERNATIONAL TELEPHONE CONNECTIONS AND CIRCUITS GENERAL CHARACTERISTICS COMMON TO ALL ANALOGUE CARRIERTRANSMISSION SYSTEMS INDIVIDUAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON METALLIC LINES GENERAL CHARACTERISTICS OF INTERNATIONAL CARRIER TELEPHONE SYSTEMS ON RADIO-RELAY OR SATELLITE LINKS AND INTERCONNECTION WITH METALLIC LINES COORDINATION OF RADIOTELEPHONY AND LINE TELEPHONY TRANSMISSION MEDIA AND OPTICAL SYSTEMS CHARACTERISTICS General Symmetric Symmetric cable pairs Land coaxial cable pairs Submarine cables Free space optical systems Optical fibre cables Characteristics of optical components and subsystems Characteristics of optical systems DIGITAL TERMINAL EQUIPMENTS DIGITAL NETWORKS DIGITAL SECTIONS AND DIGITAL LINE SYSTEM MULTIMEDIA QUALITY OF SERVICE AND PERFORMANCE – GENERIC AND USERRELATED ASPECTS TRANSMISSION MEDIA CHARACTERISTICS DATA OVER TRANSPORT – GENERIC ASPECTS PACKET OVER TRANSPORT ASPECTS ACCESS NETWORKS
G.100–G G.200–
G.300–
G.400–
G.450–G G.600–G G.600– G.610– G.620– G.630– G.640– G.650– G.660– G.680– G.700–G G.800–G G.800– G.900–G G.1000
G.6000– G.7000 G.8000– G.8000 G.9000
For further details, please refer to the list of ITU-T Recommendations.
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Recommendation ITU-T G.657 Characteristics of a bending-loss insensitive single-mode optical fibre and cable for the access network
Summary
Worldwide, technologies for broadband access networks are advancing rapidly. Among th technology applying single-mode fibre provides for a high-capacity transmission medium wh answer the growing demand for broadband services.
The experience with the installation and operation of single-mode fibre and cable based netw huge, and Recommendation ITU-T G.652 describing its characteristics has been adapted experience. Nevertheless, the specific use in an optical access network puts different demand fibre and cable which impacts its optimal performance characteristics. Differences with re the use in the general transport network are mainly due to the high density network of dist and drop cables in the access network. The limited space and the many manipulations operator-friendly fibre performance and low bending sensitivity. In addition, the cabling You're Reading a Preview crowded telecom offices where space is a limiting factor has to be improved accordingly.
It is the aim of Recommendation ITU-T G.657 to support Unlock full access with a free trial. this optimization by recomm strongly improved bending performance compared with the existing ITU-T G.652 single-mo and cables. This is done by means of introducing two Free categories Download With Trial of single-mode fibres, one category A, is fully compliant with the ITU-T G.652 single-mode fibres and can also be other parts of the network. The other, category B, is not necessarily compliant with ITU-T G is capable of low values of macrobending losses at very low bend radii and is pre-dom intended for in-building use.
This edition of this Recommendation includes the addition of two sub-categories in bo categories A and B. These sub-categories differ in macrobending loss. Sign up to vote on this title
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FOREWORD
The International Telecommunication Union (ITU) is the United Nations specialized agency in the telecommunications, information and communication technologies (ICTs). The ITU Telecommu Standardization Sector (ITU-T) is a permanent organ of ITU. ITU-T is responsible for studying te operating and tariff questions and issuing Recommendations on them with a view to stand telecommunications on a worldwide basis.
The World Telecommunication Standardization Assembly (WTSA), which meets every fou establishes the topics for study by the ITU-T study groups which, in turn, produce Recommendat these topics.
The approval of ITU-T Recommendations is covered by the procedure laid down in WTSA Resolutio
In some areas of information technology which fall within ITU-T's purview, the necessary standa prepared on a collaborative basis with ISO and IEC.
NOTE In this Recommendation, the expression "Administration" is used for conciseness to indicate telecommunication administration and a recognized operating agency.
Compliance with this Recommendation is voluntary. However, the Recommendation may contain You're Reading a Preview mandatory provisions (to ensure e.g., interoperability or applicability) and compliance w Recommendation is achieved when all of these mandatory provisions are met. The words "shall" full access with a free trial. other obligatory language such as "must"Unlock and the negative equivalents are used to express requireme use of such words does not suggest that compliance with the Recommendation is required of any part
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INTELLECTUAL PROPERTY RIGHTS
ITU draws attention to the possibility that the practice or implementation of this Recommendati the ev involve the use of a claimed Intellectual Property Right. ITU Sign takes position upno to vote on thisconcerning title validity or applicability of claimed Intellectual Property Rights, whether asserted by ITU members o Useful Not useful outside of the Recommendation development process.
As of the date of approval of this Recommendation, ITU had not received notice of intellectual p
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CONTENTS
1
Scope ............................................................................................................................
2
References.....................................................................................................................
3
Terms and definitions ...................................................................................................
4
Abbreviations and acronyms ........................................................................................
5
Fibre attributes .............................................................................................................. 5.1
Mode field diameter .......................................................................................
5.2
Cladding diameter ..........................................................................................
5.3
Core concentricity error ..................................................................................
5.4
6
Non-circularity .............................................................................................
5.5
Cut-off wavelength .........................................................................................
5.6
Macrobending loss..........................................................................................
5.7
Material properties of the fibre .......................................................................
5.8
Refractive index profile ..................................................................................
5.9
Longitudinal uniformity of chromatic dispersion...........................................
5.10
Chromatic dispersion coefficient for category A fibres .................................
Cable attributes ............................................................................................................. You're Reading a Preview 6.1 Attenuation coefficient ................................................................................... 6.2
7
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Polarization mode dispersion coefficient for category A fibres .....................
Tables of recommended valuesDownload .................................................................................... With Free Trial
Appendix I – Lifetime expectation in case of small radius storage of single-mode fibre ....... I.1
Introduction ....................................................................................................
I.2
Network and network failure ..........................................................................
I.3
Fibre lifetime considerations ..........................................................................
I.4
Conclusions ....................................................................................................
Bibliography............................................................................................................................. Sign up to vote on this title
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Introduction
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Worldwide, technologies for broadband access networks are advancing rapidly. Among th technology applying single-mode fibre provides for a high-capacity transmission medium can answer the growing demand for broadband services.
The experience with the installation and operation of single-mode fibre and cable based netw huge, and Recommendation ITU-T G.652 describing its characteristics has been adapted experience. Nevertheless, the specific use in an optical access network puts different dema the fibre and cable. Due to the dense distribution and drop-cable network, the limited space many manipulations in this part of the network, fibre and cable requirements may be op differently from the use in a general transport network. It is the aim of this Recommend support this optimization by recommending different attribute values for the existing ITU-T single-mode fibre and cables and by recommending other categories of single-mode fibre typ
As for the network structures in which the single-mode optical fibre cable is used, users are r to the extensive information that is available in the references listed in the bibliography.
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Recommendation ITU-T G.657 Characteristics of a bending-loss insensitive single-mode optical fibre and cable for the access network 1
Scope
This Recommendation describes two categories of single-mode optical fibre cable wh suitable for use in the access networks, including inside buildings at the end of these network categories A and B contain two sub-categories which differ in macrobending loss.
Category A fibres are suitable to be used in the O, E, S, C and L-band (i.e., throughout th to 1625 nm range). Fibres and requirements in this category are a subset of ITU-T G.652.D and have the same transmission and interconnection properties. The main modificatio improved bending loss and tighter dimensional specifications, both for improved conne Sub-category ITU-T G.657.A1 fibres are appropriate for a minimum design radius of 10 mm sub-category encompasses fully the former ITU-T G.657(12/2006).A category.
Sub-category ITU-T G.657.A2 fibres are appropriate for a minimum design radius of 7.5 mm
Category B fibres are suitable for transmission at 1310, 1550 and 1625 nm for restricted dis These fibres may have different splicing and connection properties than ITU-T G.652 fibres, capable at very low values of bend radius.
Sub-category ITU-T G.657.B2 fibres are appropriate for a minimum design radius of 7.5 mm sub-category encompasses fully the former ITU-T G.657(12/2006).B category. You're Reading a Preview Sub-category ITU-T G.657.B3 fibres are appropriate for a minimum design radius of 5 mm. Unlock full access with a free trial.
The meaning of the terms used in this Recommendation and the guidelines to be followed measurement to verify the various characteristics are given in [ITU-T G.650. Download With Free Trial [ITU-T G.650.2]. The characteristics of these fibre categories, including the definitions relevant parameters, their test methods and relevant values, will be refined as studies and exp progress. 2
References
The following ITU-T Recommendations and other references contain provisions which, t reference in this text, constitute provisions of this Recommendation. At the time of publicat editions indicated were valid. All Recommendations and Sign other references up to vote on thisare titlesubject to re users of this Recommendation are therefore encouraged to investigate the possibility of apply Useful Not useful most recent edition of the Recommendations and other references listed below. A list currently valid ITU-T Recommendations is regularly published. The reference to a documen
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IEC 60793-1-47 (2009), Optical fibres – Part 1-47; Measurement metho test procedures – Macrobending loss .
Terms and definitions
For the purposes of this Recommendation, the definitions and the guidelines to be followed measurement to verify the various characteristics are given in [ITU-T G.650. [ITU-T G.650.2]. Values shall be rounded to the number of digits given in the Recommended values before conformance is evaluated. 4
Abbreviations and acronyms
This Recommendation uses the following abbreviations and acr onyms: DGD
Differential Group Delay
PMD
Polarization Mode Dispersion
5
Fibre attributes
The optical fibre characteristics that provide the essential design framework for fibre manu system design and use in outside plant networks are recommended in [ITU-T G.652]. In this the emphasis is on attributes that optimize the fibre and cable for its use in broadband optica networks, especially its improved macrobending behaviour which supports small volum managements systems and low radius mounting in telecom offices and customer prem apartment buildings and single dwelling houses. You're Reading a Preview For completeness, also those characteristics of the fibre that provide a minimum essential full access with framework for fibre manufacture areUnlock recommended ina free thistrial. clause. Ranges or limits on val presented in the tables of clause 7. Of these, cable manufacture or installation may sign affect the cabled fibre cut-off wavelength and PMD. Otherwise, the recommended charac Download With Free Trial will apply equally to individual fibres, fibres incorporated into a cable wound on a drum an in an installed cable. 5.1
Mode field diameter
Both a nominal value and tolerance about that nominal value shall be specified at 1310 n nominal value that is specified shall be within the range found in clause 7. The specified to shall not exceed the value in clause 7. The deviation from nominal shall not exceed the sp tolerance. Sign up to vote on this title 5.2
Cladding diameter
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necessary to recommend a particular value for the mode field non-circularity. It is not n necessary to measure the mode field non-circularity for acceptance purposes. 5.4.2
Cladding non-circularity
The cladding non-circularity shall not exceed the value found in clause 7. 5.5
Cut-off wavelength
Two useful types of cut-off wavelength can be distinguished: a)
cable cut-off wavelength λ cc;
b)
fibre cut-off wavelength λc .
The correlation of the measured values of λ c and λ cc depends on the specific fibre and cable and the test conditions. While in general λ cc < λ c, a general quantitative relationship ca easily established. The importance of ensuring single-mode transmission in the minimum length between joints at the minimum operating wavelength is paramount. This may be per by recommending the maximum cable cut-off wavelength λ cc of a cabled single-mode fib 1260 nm, or for worst-case length and bends by recommending a maximum fibre wavelength to be 1250 nm. The cable cut-off wavelength, λ cc, shall be less than the maximum specified in clause 7. 5.6
Macrobending loss
Macrobending loss observed in uncabled fibres varies with wavelength, bend radius and num turns about a mandrel with a specified radius. Macrobending loss shall not exceed the ma You're Reading a Preview value given in clause 7 for the specified wavelength(s), bend radii and number of turns. Unlock full access with a free trial.
The actual low radius exposure of the fibre is on relatively short lengths only. As the typical of the bending radius and the length of the bent fibre may vary depending upon the design Downloadpractice, With Free Trial fibre management system and the installation a specification at one single bending is no longer sufficient. Although modelling results on various fibre types have been publis generally applicable bending loss model is available to describe the loss versus bend behaviour. For this reason, the recommended maximum macrobending loss is specified at d bend radii in the tables in clause 7.
While a baseline on macrobending performance can be established for uncabled fibres, th design and materials of cable construction can contribute to the resulting performance in th Macrobending loss in cabled fibre may differ from that observed in uncabled fibremeasu Sign up to vote on this title because of the bend-limiting effect of the cable structure on the fibre bend. Study is contin Useful Not useful the macrobending effects of cabling and any result in the need for additional cable specific parameters in the future.
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NOTE 3 – In the event that routine tests are required, deviating loop diameters can be used instea recommended test, for accuracy and measurement ease. In this case, the loop diameter, number of tu the maximum permissible bend loss for the several-turn test should be chosen so as to correlate recommended test and allowed loss.
NOTE 4 – In general, the macrobending loss is influenced by the choice of the values for oth attributes as the mode field diameter, chromatic dispersion coefficient and the fibre cut-off wav Optimization with respect to macrobending losses usually involves a trade-off between the values fibre attributes. NOTE 5 – A mandrel winding method (method A), which is described in [IEC 60793-1-47], can be as a measurement method for macrobending loss by substituting the bending radius and number specified in Tables 7-1 and 7-2.
5.7
Material properties of the fibre
5.7.1
Fibre materials
The substances of which the fibres are made should be indicated. NOTE – Care may be needed in fusion splicing fibres of different substances. Provisional results that adequate splice loss and strength can be achieved when splicing different high-silica fibres.
5.7.2
Protective materials
The physical and chemical properties of the material used for the fibre primary coating and way of removing it (if necessary) should be indicated. In the case of single-jacketed fibre, indications shall be given. 5.7.3
Proof stress level
You're Reading a Preview The specified proof stress, σ p, shall not be less than the minimum specified in clause 7. Unlock full access with a free trial.
NOTE 1 – The definitions of the mechanical parameters are contained in clauses 3.2 and [ITU-T G.650.1].
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NOTE 2 – See also the informative Appendix I on this subject.
NOTE 3 – The failure probability for fibre under 30 mm of radius bend as described in [ITU-T increases with decreasing bend radius. The mechanical reliability of optical fibre in this application sp function of the characteristics of the cable structure, the installation techniques and deployment con Care should be given that, for some installations, additional constraints on installation, such as high proof test levels or other factors may be required to ensure the full expected life.
NOTE 4 – It is recommended that the proof stress level applied to fibre and the required reliabil during its lifetime are agreed between supplier and customer. Sign up to vote on this title
5.8
Refractive index profile
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The Sellmeier fit in the 1310 nm region may not be sufficiently accurate when extrapolated 1550 nm region. Because the chromatic dispersion in the latter region is large, the reduced a may be acceptable; if not, it can be improved by including data from the 1550 nm regio performing the common fit, or by using a separate fit for the 1550 nm region. It should be no a common fit may reduce the accuracy in the 1310 nm region.
The chromatic dispersion coefficient, D, is specified by putting limits on the paramete chromatic dispersion curve that is a function of wavelength in the 1310 nm region. The ch dispersion coefficient limit for any wavelength, λ , is calculated with the minimum zero-dis wavelength, λ 0min, the maximum zero-dispersion wavelength, λ 0max, and the ma zero-dispersion slope coefficient, S 0max, according to:
λ S 0 max λ 0 max 1− 4 λ
4
λ S 0 max λ 0 min ( ) ≤ D λ ≤ 1− 4 λ
4
The values of λ 0min, λ 0max and S 0max shall be within the limits indicated in the tables of clause
NOTE 1 – It is not necessary to measure the chromatic dispersion coefficient of single-mode fi routine basis.
NOTE 2 – The chromatic dispersion for category B fibres is generally not critical for the applicatio category of fibres, and therefore its value is not included in the attributes listed in Table 7-2, category
6
Cable attributes
Since the geometrical and optical characteristics of fibres given in clause 5 are barely affe the cabling process, this clause You're gives Reading recommendations a Preview mainly relevant to trans characteristics of cabled factory lengths. Unlock full access with a free trial.
Environmental and test conditions are paramount and are described in the guidelines methods. Download With Free Trial 6.1
Attenuation coefficient
The attenuation coefficient is specified with a maximum value at one or more wavelengths the 1310 nm and 1550 nm regions. The optical fibre cable attenuation coefficient values s exceed the values found in clause 7.
NOTE – The attenuation coefficient may be calculated across a spectrum of wavelengths, b measurements at a few (3 to 4) predictor wavelengths. This procedure is described in clause 5 [ITU-T G.650.1] and an example is given in Appendix III of [ITU-T G.650.1]. Sign up to vote on this title
6.2
Useful Not useful Polarization mode dispersion coefficient for category A fibres
When required, cabled fibre polarization mode dispersion shall be specified on a statistica
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than or equal to that specified for the cabled fibres. The ratio of PMD values for uncabled f cabled fibres depends on the details of the cable construction and processing, as well as on th coupling condition of the uncabled fibres. [ITU-T G.650.2] recommends a low mode c deployment requiring a low tension wrap on a large diameter spool for uncabled fibr measurements.
The limits on the distribution of PMD coefficient values can be interpreted as being equivalent to limits on the statistical variation of the differential group delay (DGD), tha randomly with time and wavelength. When the PMD coefficient distribution is specified for fibre cable, equivalent limits on the variation of DGD can be determined. The metrics and for link DGD distribution limits are found in Appendix I of [ITU-T G.652].
NOTE 1 – PMDQ specification would be required only where cables are employed for systems that h specification of the max DGD, i.e., for example, PMD Q specification would not be applied to recommended in this Recommendation.
NOTE 2 – PMDQ should be calculated for various types of cables, and they should usually be ca using sampled PMD values. The samples would be taken from cables of similar construction.
NOTE 3 – The PMDQ specification should not be applied to short cables such as jumper cables cables and drop cables.
NOTE 4 – The PMD coefficient for category B fibres is generally not critical for the applicatio category of fibres and therefore its value is not included in the attributes listed in Table 7-2, category
7
Tables of recommended values
The following tables summarize the recommended values for the sub-categories of fi categories A and B that satisfy the objectives of this Recommendation. You're Reading a Preview
Table 7-1, category A attributes, contains the recommended attributes and values needed to Unlock full access with a free trial. optimized access network installation with respect to macrobending loss, while the recom values for the other attributes still remain within the range recommended in ITU-T G.652. Download With Free Trial category has two sub-categories with different macrobending requirements: ITU-T G.657.A (former ITU-T G.657(12/2006).A) and ITU-T G.657.A2 fibre.
Table 7-2, category B attributes, contains the recommended attributes and values needed to optimized access network installation with very short bending radii applied in fibre mana systems and particularly for restricted distance installations. For the mode-field diame chromatic dispersion coefficients, the recommended range of values might be outside of th of values recommended in [ITU-T G.652]. This category has two sub-categories with d macrobending requirements: ITU-T G.657.B2 (former ITU-T G.657(12/2006).B) fib Sign up to vote on this title ITU-T G.657.B3 fibre.
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Table 7-1 – ITU-T G.657 category A attributes Fibre attributes Attribute
Detail
Mode field diameter
Value
Wavelength
1310 nm
Range of nominal values
8.6-9.5 µm
Tolerance
±0.4 µm
Nominal
125.0 µm
Tolerance
±0.7 µm
Core concentricity error
Maximum
0.5 µm
Cladding non-circularity
Maximum
1.0%
Cable cut-off wavelength
Maximum
1260 nm
Cladding diameter
Uncabled fibre macrobending loss (Notes 1, 2)
ITU-T G.657.A1
Radius (mm)
15
ITU-T G.657.
10
Number of turns
15
10
1
10 10
Max. at 1550 nm (dB)
0.25
0.75
0.03
0.1
Max. at 1625 nm (dB)
1.0
1.5
0.1
0.2
Proof stress
Minimum
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0.69 GPa
Chromatic dispersion coefficient
λ 0min
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1300 nm
λ 0max
S 0max
1324 nm
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0.092 ps/nm2 × km
Cable attributes
Attenuation coefficient
PMD coefficient
Maximum from 1310 nm to 1625 nm (Note 3)
0.4 dB/km
Maximum at 1383 nm ±3 nm (Note 4)
0.4 dB/km
Maximum at 1550 nm
0.3 dB/km
M Q Maximum PMDQ
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0.20 ps/ km
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Table 7-2 – ITU-T G.657 category B attributes Fibre attributes Attribute
Detail
Mode field diameter
Value
Wavelength
1310 nm
Range of nominal values
6.3-9.5 µm
Tolerance
±0.4 µm
Nominal
125.0 µm
Tolerance
±0.7 µm
Core concentricity error
Maximum
0.5 µm
Cladding non-circularity
Maximum
1.0%
Cable cut-off wavelength
Maximum
1260 nm
Cladding diameter
Uncabled fibre macrobending loss (Notes 1, 2)
ITU-T G.657.B2
Radius
15
Number of turns Max. at 1550 nm (dB)
Proof stress Chromatic dispersion coefficient (Note 3)
10 10
7.5 1
0.1
10 1
7.5 1
0.5
0.03
0.08
Max. at 1625 nmYou're (dB) Reading 0.1 a 0.2 Preview 1.0
0.1
0.25
Minimum
0.03
ITU-T G.657.B3
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0.69 GPa
TBD
Cable attributes
Attenuation coefficient
PMD coefficient (Note 4)
Maximum at 1310 nm
0.5 dB/km
Maximum at 1550 nm
0.3 dB/km
Maximum at 1625 nm
0.4 dB/km TBD
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method (method A of NOTE 1 – The macrobending loss can be evaluated using a mandrel winding [IEC 60793-1-47]), substituting the bending radius and the number of turns specified in this table. NOTE 2 – While a baseline on macrobending performance can be established for uncabled fibres, th Useful
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To illustrate the different macrobending specifications of the various sub-categories defined clause, the recommended values have been represented in Figures 7-1 and 7-2 .
Figure 7-1 – Macrobending loss data from Tables 7-1, category A
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Figure 7-2 – Macrobending loss data from Tables 7-2, category B
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Appendix I
Lifetime expectation in case of small radius storage of single-mode fibr (This appendix does not form an integral part of this Recommendation) I.1
Introduction
Fibre storage at reduced radius in fibre management systems and in closures may impose co with respect to the fibre lifetime expectation. Important parameters that determine the e lifetime are the applied proof stress level when producing the fibre and the intrinsic strength fibre. The required values of these parameters have to be offset against the accepted failure the network. In assessing the result of this, the major question is whether the single-mode f specified in this Recommendation fulfil the requirements for a sufficiently long expectation. In this appendix, more background is given on this question. I.2
Network and network failure
For the lifetime calculations, a simple network is considered to consist of a 1000-fibre distr cable with a tree structure as indicated in Figure I.1. Depending upon the installation and cu connection procedures of the operator, the individual fibres or groups of fibres are st cassettes in the main distribution cable or in the branches. For simplicity and as a wo situation, it is assumed that all 1000 fibres pass five cabinets or enclosures with a storage cas every individual fibre link and in every cabinet or enclosure. You're Reading a Preview Unlock full access with a free trial.
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Figure I.1 – Simplified network structure
In this particular network structure, a failure rate per individual single fibre cassette of 0.0 in th 20 years, results in a 5% probability that in 20 years one single spontaneous break Sign up to vote on this title network. This probability has to be compared with the probability of other failures that ma Useful Not useful in the distribution network during the 20-year operational lifetime. Causes for this are in the due to re-work or re-configuration in the link or due to other causes of cable or cabinet dama most access network situations, it may be assumed that the stated failure probability
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function of the fibre bend radius is indicated in Figure I.2 for different values of the stati corrosion susceptibility coefficient, n (fatigue parameter).
Figure I.2 – Maximum storage length for a bent fibre and different values of the fatigue parameter, n
Note that a value of n = 18 is the minimum value as stated in [b-IEC 60793-2-50] and in Te Generic Requirements for Optical Fiber and Optical Fiber Cable (GR-20-CORE). For a length per cassette of, for example, 100 cm, i.e., 2 × 50 cm for one single fibre, the bend rad be lowered from the current 30 mm value down to 15 or even 9 mm depending upon the gua n- value without violating the 0.001% failure rate per cassette in 20 years.
A second storage issue is at the entrance and exit ports in the fibre management syste You're network Reading acomponents Preview required small volume for optical access is not only dependent up storage area, but also on the minimum bend radius of the input and exit ports. The effect of Unlock full access with a free trial. be taken into account in several ways. For the purpose of this appendix, it is assumed that i storage cassette four additional 90-degree bends are required for guiding the fibres into and With Freefailure Trial rate due to these additiona the storage areas. It is also assumed Download that the additional should be limited to less than 10% of the accepted failure rate of 0.001% per cassette. This re the minimum values as indicated in the middle column of Table I.1. Table I.1 – Minimum value of non-storage bend radii n-
value
Four 90° bends
18
Rmin = 15.0 mm
22
Rmin = 11.1 mm
29
Rmin = 8.0 mm
Single 180° bend
Rmin = 12.6 mm
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Rmin = 6.6 mm
In the right column, the minimum radius in case of a single 180-degree erroneous bend is
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Conclusions
The examples given in clause I.3 show that rather detailed knowledge on a realistic deploy the fibre in a real-life distribution network is required to perform a reliable prediction operational lifetime. But even under the rather severe assumptions used in these examples shows that for the reduction of the fibre storage radii into a much lower range than the c applied 30 mm, the current lifetime characteristics of the single-mode fibre as spec [ITU-T G.652] are sufficient to support a 20-year operational lifetime.
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Bibliography
[b-ITU-T G.671]
Recommendation ITU-T G.671 (2009), Transmission characteristics optical components and subsystems .
[b-ITU-T G-Sup.39]
ITU-T G-series Recommendations – Supplement 39 (2008), Optical design and engineering considerations .
[b-ITU-T L.13]
Recommendation ITU-T L.13 (2003), Performance requirements for passive optical nodes: Sealed closures for outdoor environments .
[b-ITU-T L.42]
Recommendation ITU-T L.42 (2003), Extending optical fibre solutio the access network .
[b-ITU-T L.65]
Recommendation ITU-T L.65 (2006), Optical fibre distribution of ac networks.
[b-ITU-T L.66]
Recommendation ITU-T L.66 (2007), Optical fibre cable maintenan criteria for in-service fibre testing in access networks .
[b-ITU-T ANT]
Access Network Transport Standards Overview.
[b-IEC 60793-2-50]
IEC 60793-2-50 (2004), Optical fibres – Part 2-50: Product specifica Sectional specification for class B single-mode fibres .
[b-IEC/TR 62048]
IEC/TR 62048 (2002), Optical fibres – Reliability – Power law theor You're Reading a Preview Matthijsse, P., and Griffioen, W. (2005), Matching optical fiber lifeti Unlock full access with a free trial. bend-loss limits for optimized local loop fiber storage , Optical Fibre Technology, Vol. 11, No. 1, January, pp. 92-99. Download With Free Trial
[b-OFT]
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SERIES OF ITU-T RECOMMENDATIONS Series A
Organization of the work of ITU-T
Series D
General tariff principles
Series E
Overall network operation, telephone service, service operation and human factors
Series F
Non-telephone telecommunication services
Series G
Transmission systems and media, digital systems and networks
Series H
Audiovisual and multimedia systems
Series I
Integrated services digital network
Series J
Cable networks and transmission of television, sound programme and other multimedia
Series K
Protection against interference
Series L
Construction, installation and protection of cables and other elements of outside plant
Series M
Telecommunication management, including TMN and network maintenance
Series N
Maintenance: international sound programme and television transmission circuits
Series O
Specifications of measuring equipment
Series P
Terminals and subjective and objective assessment methods
Series Q
Switching and signalling
Series R
Telegraph transmission
Series S
Telegraph services terminal equipment
Series T
Terminals for telematic services
Series U
Telegraph switching
Series V
Data communication over the telephone network
Series X
Sign up to vote on this title Data networks, open system communications and security
Series Y
Global information infrastructure, Internet protocol aspects and next-generation networ
Series Z
Languages and general software aspects for telecommunication systems
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