ASD-STAN/D 2/S 10 - Optical

This document specifies the general requirements for the methods of testing elements of electrical, optical and data transmission system connections used in aerospace applications.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a bend-insensitive, 50 µm/125 µm Graded Index fibre core, 1,8 mm outside diameter for non pull-proof contact designs.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 50/125 µm Graded Index fibre core, 1,8 mm outside diameter for non-pull-proof contact designs.

This document specifies a method of measuring the semi loose effect of a semi loose cable.
Pull proof optical contacts are used. The optical contact (ferrule) is longitudinally moving to preserve the optical performance even when cables are pulled.
Consequently, the buffered fibre moves beneath the strength members (called semi loose effect).
This document describes a test methodology to assess the quality of the cable when contact is pulled or pushed.

This document evaluates the resistance of the fiber optic cable to humidity changes at different
temperatures.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 9/125 µm, SM fibre core, and 1,8 µm outside cable diameter and of semi loose buffer construction.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 62,5/125 µm, MM fibre core, and 900 µm outside cable diameter and of semi-loose buffer construction for "inside avionics box" equipment fibre harnessing.

This European product Standard specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 9/125 µm. Single mode fibre core, 2,74 mm outside cable diameter and of semi-loose construction. The basic construction is the cable defined in EN 4641-102 with added sheaths for ruggedized usages.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 9/125 µm, MM fibre core, and 900 µm outside cable diameter and of semi loose buffer construction for "inside avionics box" equipment fibre harnessing.

This European Standard describes the procedure to measure the withdrawal force between the ferrule of an optical contact and the resilient alignment sleeve located inside the connector.
This method is suitable for use for resilient alignment sleeve qualification.
It shall be used together with EN 2591-100.

This European Standard specifies the general characteristics, conditions for qualification, acceptance and quality assurance, as well as the test methods and groups for fibre optic cables with a cladding of 125 µm outside diameter.

This handbook considers the best practices during initial design and how the practices chosen affect through life support of the installation. Looming and installation practices are a critical aspect of any aircraft electrical/avionics installation. In order to provide a reliable and efficient system, it is important that the fibre optic installation is designed for reliability and maintainability.
This document provides technical advice and assistance to designers and engineers on the incorporation of fibre optic harnesses into an airframe, while, wherever possible, maintaining maximum compliance with current aircraft electrical harness procedures.
All topics that are related to the installation of optical cables are addressed in EN 3197.
These rules are applicable for fibre optic cables and connectors defined by EN specifications.

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...

This document examines the requirements to enable accurate measurement of fibre optic links from start of life and during the life cycle of the system from installation and through-service. This document explains the issues associated with optical link measurement and provides techniques to address these issues. This document discusses the measurement of key parameters associated with the passive layer (i.e. transmission of light through an optical harness). This document does not discuss systems tests, e.g. bit error rates.

This document specifies a method of determining the attenuation variation of an optical cable during mechanical bending under load at the maximum and minimum operating temperatures.

This document specifies the general characteristics, the conditions for qualification, acceptance and quality assurance, as well as the test programs and groups for EN 4165 rectangular connectors with removable module and two EN 4734 MT contacts.

This document specifies the performance and dimensions of MT male contact 12 ways for EN 4733-001 connector specification.

This document specifies the performance and dimensions of MT female contact 12 ways for EN 4733-001 connector specification.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 62,5 µm/125 µm simplex fibre, 2,74 mm outside cable diameter and of semi-loose construction. The basic construction is the cable specified in EN 4641-102 with added sheaths for ruggedized usages.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 62,5 µm/125 µm graded index fibre nominal, 1,8 mm outside diameter and of semi-loose buffer construction.

This document specifies permissible cables and materials used in the manufacturing of EN 4733-003 module and EN 4734-10X optical MT contact.

This document specifies the characteristics of module double contacts MT for EN 4734-10X optical MT contacts, used in the family of rectangular, modular, connectors EN 4165 series.

This document details the dimensions and performance requirements of a multimode female size 16, non-physical contact expanded beam terminus. This terminus is suitable for use with connectors which have standard size 16 socket crimp contact cavities (series I and III): connectors with cavities for contact of type EN 3155-009F16.

This document details the dimensions and performance requirements of a multimode male size 12, non-physical contact expanded beam terminus. This terminus is suitable for use with connectors which have standard size 12 pin crimp contact cavities: connectors with cavities for contact of type EN 3155-008M12.

This document specifies the general characteristics, the conditions for qualification, acceptance and quality assurance, as well as the test programs and groups for threaded ring coupling circular connectors with expanded beam termini, intended for use in a temperature range from −55 °C to 125 °C continuous.

This document details the dimensions and performance requirements of a multimode female size 12, non-physical contact expanded beam terminus. This terminus is suitable for use with connectors which have standard size 12 socket crimp contact cavities (series I and III): connectors with cavities for contact of type EN 3155-009F12.

This document details the dimensions and performance requirements of a multimode male size 16, non-physical contact expanded beam terminus. This terminus is suitable for use with connectors which have standard size 16 pin crimp contact cavities: connectors with cavities for contact of type EN 3155-008M16.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance, as well as the test methods and groups for fibre optic cables with a cladding of 125 µm outside diameter.

This document specifies the general characteristics, conditions for qualification, acceptance and quality assurance for a fibre optic cable with a 50/125 μm Graded Index fibre core, 1,8 mm outside diameter for non pull-proof contact designs.