prEN 4533-001
(Main)Aerospace series - Fibre optic systems - Handbook - Part 001: Termination methods and tools
Aerospace series - Fibre optic systems - Handbook - Part 001: Termination methods and tools
1.1 General
This document examines the termination of optical fibre cables used in aerospace applications. Termination is the act of installing an optical terminus onto the end of a buffered fibre or fibre optic cable. It encompasses several sequential procedures or practices. Although termini have specific termination procedures, many share common elements and these are discussed in this document. Termination is required to form an optical link between any two network or system components or to join fibre optic links together.
The fibre optic terminus features a precision ferrule with a tight tolerance central bore hole to accommodate the optical fibre (suitably bonded in place and highly polished). Accurate alignment with another (mating) terminus is provided within the interconnect (or connector) alignment mechanism. As well as single fibre ferrules, it is noted that multi-fibre ferrules exist (e.g. the MT ferrule), and these are also discussed in this document.
Another technology used to connect 2 fibres is the expanded beam. 2 ball lenses are used to expand, collimate and then refocus the light from and to fibres. Contacts are not mated together. It helps reducing the wear between 2 contacts and allows more mating cycles. This technology is less sensitive to misalignments and dust. Losses are remaining more stable than butt joint contact even if the nominal loss is higher.
NOTE Current terminology in the aerospace fibre optics community refers to an optical terminus or termini. The term optical contact can be seen in some documents and has a similar meaning. However, the term contact is now generally reserved for electrical interconnection pins. The optical terminus (or termini) is housed within an interconnect (connector is an equivalent term). Interconnects can be single-way or multi-way. The interconnect or connector will generally house the alignment mechanism for the optical termini (usually a precision split-C sleeve made of ceramic or metal). It is important that the reader is aware of these different terms.
An optical link can be classified as a length of fibre optic cable terminated at both ends with fibre optic termini. The optical link provides the transmission line between any two components via the optical termini which are typically housed within an interconnecting device (typically a connector) with tight tolerancing within the alignment mechanisms to ensure a low loss light transmission.
This document explains the need for high integrity terminations, provides insight into component selection issues and suggests best practice when terminating fibres into termini for high integrity applications. A detailed review of the termination process can be found in Clause 4 of this document and is organized in line with the sequence of a typical termination procedure.
The vast number of cable constructions and connectors available make defining a single termination instruction that is applicable to all combinations very difficult. Therefore, this handbook concentrates on the common features of most termination practices and defining best practice for current to near future applications of fibre optics on aircraft. This has limited the studies within this part to currently available ‘avionic’ silica fibre cables and adhesive filled butt-coupled type connectors. Many of the principles described, however, would still be applicable for other termination techniques. Other types of termination are considered further in EN 4533-004.
It is noted that the adhesive based pot-and-polish process is applicable to the majority of single-way fibre optic interconnects connectors and termini for multi-way interconnects and connectors. They share this commonality.
1.2 Need for high-integrity terminations
In order to implement a fibre optic based system on an aircraft, it is vital to ensure that all the constituent elements of the system will continue to operate, to specification, over the life of the system...
Luft- und Raumfahrt - Faseroptische Systeme - Handbuch - Teil 001: Anschlussverfahren und Werkzeuge
Série aérospatiale - Systèmes des fibres optiques - Manuel d'utilisation - Partie 001 : Méthodes et outils de terminaison
Aeronavtika - Sistemi iz optičnih vlaken - Priročnik - 001. del: Metode določanja in orodja
General Information
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Standards Content (Sample)
SLOVENSKI STANDARD
01-junij-2024
Aeronavtika - Sistemi iz optičnih vlaken - Priročnik - 001. del: Metode določanja in
orodja
Aerospace series - Fibre optic systems - Handbook - Part 001: Termination methods and
tools
Luft- und Raumfahrt - Faseroptische Systeme - Handbuch - Teil 001:
Anschlussverfahren und Werkzeuge
Série aérospatiale - Systèmes des fibres optiques - Manuel d'utilisation - Partie 001 :
Méthodes et outils de terminaison
Ta slovenski standard je istoveten z: prEN 4533-001
ICS:
33.180.10 (Optična) vlakna in kabli Fibres and cables
49.060 Letalska in vesoljska Aerospace electric
električna oprema in sistemi equipment and systems
2003-01.Slovenski inštitut za standardizacijo. Razmnoževanje celote ali delov tega standarda ni dovoljeno.
DRAFT
EUROPEAN STANDARD
NORME EUROPÉENNE
EUROPÄISCHE NORM
March 2024
ICS 49.060 Will supersede EN 4533-001:2020
English Version
Aerospace series - Fibre optic systems - Handbook - Part
001: Termination methods and tools
Série aérospatiale - Systèmes des fibres optiques - Luft- und Raumfahrt - Faseroptische Systeme -
Manuel d'utilisation - Partie 001 : Méthodes des Handbuch - Teil 001: Anschlussverfahren und
terminaisons et des outils Werkzeuge
This draft European Standard is submitted to CEN members for enquiry. It has been drawn up by the Technical Committee ASD-
STAN.
If this draft becomes a European Standard, CEN members are bound to comply with the CEN/CENELEC Internal Regulations
which stipulate the conditions for giving this European Standard the status of a national standard without any alteration.
This draft European Standard was established by CEN in three official versions (English, French, German). A version in any other
language made by translation under the responsibility of a CEN member into its own language and notified to the CEN-CENELEC
Management Centre has the same status as the official versions.
CEN members are the national standards bodies of Austria, Belgium, Bulgaria, Croatia, Cyprus, Czech Republic, Denmark, Estonia,
Finland, France, Germany, Greece, Hungary, Iceland, Ireland, Italy, Latvia, Lithuania, Luxembourg, Malta, Netherlands, Norway,
Poland, Portugal, Republic of North Macedonia, Romania, Serbia, Slovakia, Slovenia, Spain, Sweden, Switzerland, Türkiye and
United Kingdom.
Recipients of this draft are invited to submit, with their comments, notification of any relevant patent rights of which they are
aware and to provide supporting documentation.
Warning : This document is not a European Standard. It is distributed for review and comments. It is subject to change without
notice and shall not be referred to as a European Standard.
EUROPEAN COMMITTEE FOR STANDARDIZATION
COMITÉ EUROPÉEN DE NORMALISATION
EUROPÄISCHES KOMITEE FÜR NORMUNG
CEN-CENELEC Management Centre: Rue de la Science 23, B-1040 Brussels
© 2024 CEN All rights of exploitation in any form and by any means reserved Ref. No. prEN 4533-001:2024 E
worldwide for CEN national Members.
Contents Page
European foreword . 4
Introduction . 5
1 Scope . 6
1.1 General. 6
1.2 Need for high-integrity terminations . 6
2 Normative references . 7
3 Terms and definitions . 7
4 Component selection . 7
4.1 Elements . 7
4.2 Fibre optic cables . 7
4.2.1 General. 7
4.2.2 Cable construction . 8
4.2.3 Fibre choice . 9
4.2.4 Cladding materials . 11
4.3 Primary buffer materials . 11
4.3.1 Function . 11
4.3.2 Acrylate. 12
4.3.3 Polyimide . 12
4.3.4 Silicone. 12
4.3.5 Strength members . 12
4.4 Outer jacket . 13
4.5 Fibre optic interconnects (connectors) . 13
4.5.1 Introduction . 13
4.5.2 The optical interface . 14
4.5.3 Single-way interconnects/connectors . 20
4.5.4 Multi-way interconnects/connectors . 20
4.5.5 Choice of tooling . 21
5 Health and safety aspects . 22
5.1 General. 22
5.2 Chemicals . 22
5.3 Sharps. 23
6 Termination process . 23
6.1 Objective . 23
6.2 Cable preparation . 24
6.2.1 General. 24
6.2.2 Cutting to length . 24
6.2.3 Removal of outer jacket . 25
6.2.4 Cable handling tools (gripping the cable) . 30
6.2.5 Strength member trimming/removal . 31
6.3 Removal of secondary coating(s) . 32
6.4 Removal of primary coatings . 32
6.4.1 General. 32
6.4.2 Mechanical techniques for primary coating removal . 33
6.4.3 Alternative techniques . 39
6.4.4 Troublesome coatings — Polyimide and Silicone . 40
6.4.5 Evidence of strength reduction when stripping primary buffer coatings . 42
6.4.6 To clean or not to clean . 43
6.5 Adhesives . 44
6.5.1 General . 44
6.5.2 Adhesive types . 44
6.5.3 The importance of glass transition temperature (T ) . 46
g
6.5.4 Epoxy cure schedule . 48
6.5.5 Usability . 50
6.5.6 Qualification . 54
6.6 Connector preparation . 54
6.6.1 Dry fitting . 54
6.7 Attachment of fibre to the terminus . 56
6.7.1 Application of adhesive . 56
6.7.2 Inserting fibre ‘best-practice’ . 59
6.8 Adhesive cure . 63
6.8.1 General . 63
6.8.2 Orientation . 63
6.8.3 Curing equipment . 63
6.9 Excess fibre removal . 67
6.9.1 General . 67
6.9.2 Post-cure rough cleaving . 67
6.9.3 Pre-cleave . 69
6.9.4 Safety . 69
6.9.5 Cleaving tools . 69
6.9.6 Sprung blade hand tools . 70
6.9.7 Cleaving fibres in mult
...
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