The Cable Selection Guide has been designed to assist with the selection of cable constructions typically used in today’s fibre optic industry. In all cases, a combination of the application and the environment in which the cable will be installed will call for differing cable construction requirements.

The guide is applications based and, in its first section, provides the full spectrum of applications coverage for copper, multimode fibre and singlemode fibre together with a table of optical performance. Whether indoor, outdoor, loose tube, tight buffered riser or duct, the Guide helps to provide the correct selection. Other sections cover Cable Materials, Cable Types, Applications, Installation Considerations, Standard Specifications, and a Glossary of Terms.

This TSD defines requirements for FIA-compliant cords - be they patch cords, equipment cords, mode conditioning cords or simple pigtails. How cords are tested, identified, labelled, used and maintained can have a significant effect on network reliability - as users of high bit rate multimode networks are beginning to find out.

Providing a template for a user guide for optical fibre cabling is a direct response to the requirements BS 6701:2004. It links design objectives, component usage, operational safety such that users have clear instructions for their operation, repair and maintenance of their installations.

The majority of optical fibre transmission systems deliver a signal in one direction on one optical fibre and receiving a signal on another, separate optical fibre. Groups of applications covered by such signalling schemes include virtually all of the local and wide area network technologies.
In the past the management of polarity of such transmission channels was the responsibility of the user and was achieved by the correct connection of equipment cords at either end of the installed cabling (in many cases by simple trial and error).

The growth in popularity of duplex and array interfaces, which prevents simple re-configuration of the equipment cords, requires that recommendations be prepared to allow management of channel polarity in the most appropriate manner. In addition, future network solutions may utilise parallel optical fibre elements terminated with array interfaces.

This document provides such recommendations and, providing that its recommendations are followed, allows users and installers to clearly specify the polarity maintenance approach in order to maximise channel reliability.

Current specifications for the installation of optical fibre are often needlessly stringent, bearing little relevance to the operational requirements of a cabling system or the practicalities of meeting such a specification. This document defines an approach to, and limits for, commercially viable splice loss specifications whilst ensuring the operational requirements of a cabling system are not compromised.
The approach and limits herein have been developed by analysing the key operational requirements of a typical transmission system. Any given cabling channel will have a defined optical budget - the distribution of losses within that channel being irrelevant providing that the total channel loss is sufficiently low to meet that budget. It is, therefore, not necessary (and even counterproductive) to specify maximum individual splice losses except where the level of loss indicates that there has been a fault in the splicing process (in excess of 0.3dB when splicing "same product" singlemode or multimode optical fibres).

With regard to jointing of singlemode optical fibres this document recognises that although modern fusion splicing machines have been optimised to reduce the splice loss to a minimum, mode field diameter mismatch can still be a major source of splice loss between two singlemode optical fibres. An analysis of the different IEC specifications for singlemode optical fibre shows that fibres within the same generic group can have mode field mismatches that will produce significant splice losses. Monte Carlo statistical modelling techniques used to model splice losses between "same product" fibres, "same generic type" fibres, "different type" fibres and "unknown" fibres show the effect of mode field mismatch on individual and average splice loss.

From these results and from additional data from splicing equipment manufacturers, reasonable and commercially viable average splice loss limits are defined for the various fibre types. Typical levels of rework are calculated where the FIA limits are not adopted, and the cost implications are discussed. A technical checklist of the correct splicing and fibre preparation procedures required is provided to ensure that these recommended maximum splice loss limits are achievable.

There are a number of international, European and British standards that define the correct test procedures to be used to measure the attenuation of the different link configurations and channels. In addition there are United States standards that cover the same topics. The unanimity amongst the standards is total. However, all the standards are written around test equipment that tests in one direction only and does not allow for the recent development of small form factor connectors, some of which feature asymmetric constructions. This document has been written to extend the application of these standards to a wider range of test equipment and connecting hardware.

An OTDR is possibly the most useful analytical tool available to the installer and user of optical fibre cabling. It can be used to perform inspection and testing of optical fibre cabling of all types and at all stages of installation. The soft and hard copy results produced can be included in contract documentation and represent performance baselines against which subsequent measurements can be compared. An OTDR can detect and locate the presence of poor installation practices or modifications to the installed environment. In addition, the OTDR may be used to test completed installations and provides an accurate assessment or measurement (depending upon how it is used) of the position of, and the attenuation levels produced at, the various interfaces and joints throughout the installed cabling.

However, OTDR equipment does have limitations and unskilled use can produce meaningless results. The purpose of this document is to ensure that the OTDR characterizations undertaken are made to a common standard enabling sensible interpretation of the information portrayed.

This TSD defines requirements for FIA-compliant test cords in accordance with ISO/IEC 14763-3. How cords are tested, identified, labelled, used and maintained can have a significant effect on measured results.

This document addresses the latest developments in the definition of Classes of the LED and LASER devices that are used in optical transmission systems. These definitions have been amended in 2001, so this document provides information that is as up-to-date as possible. The document also explains why the different Classes are needed. It is not simply an issue of the optical power involved, although this is a key consideration. The nature of the issue is affected by the transparency of the cornea, which varies over the wavelength range in question. At some wavelengths the cornea is transparent, so the radiation will penetrate to the retina. This may be damaged it if the power levels are excessive. At others the cornea is opaque, so it will be here that the optical energy will be dissipated. Also, if the light is in the visible part of the spectrum, the eye may be protected by the ‘blink’ reaction. Methods of providing protection range from defining work areas, such that only trained individuals are permitted to access areas defined as hazardous, through the design of equipment such that dangerous light levels are not accessible (shutters, etc), to individual protection by the wearing of goggles.

This document identifies the chemicals that are particularly relevant to the manufacture of passive fibre optic products. These include chemicals used in the manufacture of optical fibre cable (filling compounds), in performing termination of the fibres (adhesives, polishing and cleaning compounds) and in various maintenance activities (cleaning and degreasing compounds). The nature of the issues involved is described, and the relevant existing Standards and legislation identified. Information on the COSHH regulations and RIDDOR is also included. Above all, recommendations are made as to the practises to be adopted, and how these may be implemented.

This document addresses the disposal of the shards of bare optical fibre that are the waste product from the termination or splicing of optical fibre cable. These, although small, can easily penetrate the skin and cause painful inflammation and infection. Since the termination and splicing processes are manual, the shards can be transferred to other areas such as the mouth and eyes. The potential consequences of this could be serious. If shards are ingested, they can not be detected by normal methods of analysis including X-rays. Clearly it is important to implement effective procedures for the disposal of shards. The coverage of this issue by existing Standards can be traced to BS 7718, which was originally published by the FIA as the Code of Practice for Cabling Installation. This new FIA document includes recommendations as to the practices to be adopted, and how these may be implemented.