INTELLIGENT BRANDS // Cabling
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The importance of cleanliness when handling fibre
In this latest whitepaper from Excel Networking , the company discusses one of the most basic and important procedures for the maintenance of fibre optic systems is to clean the fibre optic equipment .
One of the most basic and important procedures for the maintenance of fibre optic systems is to clean the fibre optic equipment .
Any contamination in the fibre connection can cause failure of the component or failure of the whole system . Even microscopic dust particles can cause a variety of problems for optical connections . In a survey carried out by Fluke Networks they claim that 85 % of the failing links can be attributed to ‘ end-face contamination ’.
To illustrate this it can be compared to a typical human hair which is between 50 and 75 micron . A dust particle can be as little as 9 micron and is pretty much impossible to see without a microscope . Despite this it could completely block a single mode fibre core , and if trapped between two fibre faces it can even scratch the glass , damaging the end-face . If this happens then at best it will require the careful and time consuming process of being polished out and , at worst , it will have to be replaced .
A recent incident was reported claiming that fibre cable was failing after less than 10 years of use , when it shouldn ’ t degrade at all over this period of time . The first clue to the culprit of the problem was that the building and cabling infrastructure had transferred ownership on two separate occasions during this time . Each time , there was a massive opportunity to introduce contamination , which in reality is what had occurred .
There are many excellent documents which cover the correct procedure for cleaning and inspecting fibre optic end-faces , however we should always defer to the standards if they are available . In February 2010 the British Standards Institute published BS EN 61300-3-35 Examinations and Measurements- Fibre optic connector end-face visual and automated inspection . This document outlines the criteria for the number and details of the scratches and defects that can appear on the
Furthermore , with high power lasers now in use , if the contamination remains in place when the laser is turned on it can actually be burned into the end-face to such an extent that it cannot be polished out .
Whilst this may seem extreme consequences , each time you disconnect and re-connect a fibre connector problems can be re-introduced ; a statement backed by a study carried out by NEMI ( National Electronics Manufacturing Initiative )
The study showed that mating caused loose contaminants to spread . Through connection , a significant amount of the particles were transferred from the contaminated connector to the clean reference connector in a pattern similar to that seen on the contaminated connector .
Even the use of ‘ dirty ’ dust caps can have a significant impact on the ‘ cleanliness ’ of the fibre installation . The oil from human skin can also have a dramatic effect when viewed under a microscope .
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