ANALYSIS OPINION
@fibresystemsmag |
www.fibre-systems.com
A fluid situation
Mike Jones, vice-president of MicroCare, describes the use of fluids other than alcohol for cleaning fibre optic connectors
D
uring the 1970s, Bell Labs was busy perfecting the technologies to commercialise fibre optic communications. Tey could see a
time when all the copper wire in the world could not handle the volume of data that people would want to send over phone lines. One of the issues with which they struggled
was finding suitable ways to quickly and consistently clean the delicate fibre optic connectors. Tey found that even the slightest contamination on the end-faces significantly degraded the performance of their networks. Te scientists at Bell Labs recommended using only 99 per cent reagent grade isopropyl alcohol (also known as ‘IPA’ and ‘rubbing alcohol’) for cleaning their fibre optic connectors. Tey made this recommendation for two
16 FIBRE SYSTEMS Issue 5 • Autumn 2014
reasons: it was readily available, and it worked. It worked because the solvent provided additional chemical action to enhance the mechanical action provided by the cleaning device. Alcohol and other solvents were also effective at soſtening, loosening and/or dissolving dried-on contaminants and particulate. Since that time much has changed. Fibre
optics technologies are no longer the exclusive technology of the monolithic phone company but an enabling capability of almost every company. Mobile video on demand has created demand for greater bandwidth. Computing technology has plummeted in cost and expanded in capability. All of this means networks have become larger, commonplace and faster – but fibre networks, as they have become ubiquitous, have also become more fragile. Today’s fibre, while more capable, is positively
delicate. Te first fibre link that Bell Labs built in 1976 operated at 44.7 Mhz. Te lasers generated a pulse of light that was enormously long by today’s standard. But as fast as it seemed at the time, in today’s world 44.7 Mhz is positively slow. Modern networks work at gigahertz speeds which means the pulse of light is just inches long.
Such an ephemeral signal is easily ‘knocked off the rails’ by the slightest contamination on the end-faces.
Time for change Everything has changed, except that technicians around the globe are still trying to clean their fibre with IPA. Tis is no longer a good idea. First, reagent-grade IPA is not readily available
to fibre optic technicians, and ordinary alcohol is completely unsuitable for cleaning fibre optics. For example, drug store IPA is not an optical- grade cleaner because it always is diluted with 30 per cent water to lower the cost. Te mixture is packaged in a plastic container from which all sorts of plasticisers and contaminates may leach. Te container may be re-used, and it certainly will become contaminated over time. Next, alcohol actually isn’t a very good cleaner.
In terms of solvent technology, it’s pretty far down on the list of ‘old technologies’. It has a very low density, so it cannot easily clean particulate. It has a high boiling point so it is relatively slow to dry. It is easily saturated, so it will no longer be effective. Modern cleaning chemistries usually try to avoid, or at least minimise, the presence of
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