ISE Magazine, August 2018

I S E I C T S O L U T I O N S E D U C AT I O N 1 0 8 FIBER There is good news however We recently surveyed our newsletter readers regarding connector cleaning and inspection and the results make me hopeful See Figure 1 2 Avoid bending losses There are so many places where we unknowingly introduce an excessive bend or pinch point See Figure 2 In training we teach students about microbends and macrobends to provide an understanding of what can go wrong It is easy to reduce the likelihood of bending issues by focusing on proper routing handling or securing of fibers and cables Problems generally happen when dressing out splice trays or entering patch panels Damaging bends can be caused by pulling too tightly on a tie wrap or closing a cover on a stray fiber loop or not managing slack properly 3 Be aware and be careful Use the right hardware clips straps and fiber management both in and out of closures racks panels etc Follow manufacturers instructions on how much jacket to strip back how much furcation is needed and fiber strip lengths These have been provided for a reason so that everything can properly be stored in the fiber management hardware provided 4 Dont connect mismatched connectors Sure this is an easy one but we still see it happen dont plug an SC UPC connector into an adapter that has an SC APC connector on the other side See Figure 3 And dont use a multimode adapter to mate single mode connectors There is a reason that those adapters cost less than the SM versions The sleeves have less tight tolerances and the material is a bit less rigid This leads to less precise alignment of the ferrules and that creates more potential loss 5 If you troubleshoot networks and outages consider getting an optical fiber identifier OFI for your tool box OFIs can determine if there is traffic on your fiber and tell you from which direction it is coming See Figure 4 They can also pick up tones if you are working on network mapping or trying to identify what is connected to what Which leads us to another common field issue poor record keeping but we will save that for another discussion The best advice on OFIs is to do your homework before buying one The price points vary quite a bit but so does the performance Vendors specify what type of fibers and cables they can read If you have access to bare fiber you can probably use many different options If you need to check dark 900μm fibers or 2mm or 3mm simplex cables you might want to test out some options If you use a lot of bend insensitive fibers there are fewer choices I suggest you ask your favorite vendor s for a demo unit to try out before buying These are just a few of the many potential problems in the field Remember knowledge is power and it can help keep your rework and troubleshooting costs down too n Lee Kellett is General Manager Light Brigade She has more than 30 years of experience in the fiber optics industry working for AFL Corning Draka Telco Systems and several connectivity companies She has held positions in Engineering Quality Marketing and Product Management Lee holds a BS in Mechanical Engineering from Worcester Polytechnic Institute For more information please email Lee@ lightbrigade com or visit www lightbrigade com Follow Light Brigade on Twitter @ lightbrigadeinc Follow Lee Kellett on Twitter @ lhkellett Figure 2 Fiber tubes cables can be pinched or excessively bent Bends and pinch points in installed optical fibers Note the light leaking from the fiber in the tube Figure 3 When mating an UPC connector to an APC connector the resulting air gap causes excess reflection and loss Figure 4 An optical fiber identifier with screen displays that show traffic and tone detection