Rugged and Durable Fiber Optic Replacement

Optical fibers are extensively used in military aircraft, both as interconnects in electronic cards and in aircraft frames. Fiber ribbons, manufactured primarily by W.L. Gore, used in computer cards suffer significant breakage failures, usually close to the exit point of the MT connectors and at points where they have been tacked to prevent movement. Fiber cables, primarily manufactured by OFS, suffer “maintenance induced breaks” when, for example, a heavy object falls on them or they are bent sharply at an anchor point. Both these situations would benefit from development of a rugged, durable optical replacement fiber. Ideally, it should be a drop-in replacement for currently used fiber. There is significant handling associated with the bonding of optical transceivers to circuit cards which can result in broken or cracked fibers that later become failure points. Optical cables used in aircraft frames, such as JSF and F-18, are manufactured by OFS, Tensolite and General Cable. A cable made by using a high temperature thermoplastic buffer layer, as proposed by Linden, is likely to be both hermetic and strong. Programs such as JSF may benefit from development of such cables. Linden fabricated and tested an optical fiber consisting of commercial polyimide buffered fiber surrounded by a dual extruded layer high temperature thermoplastic and fluorinated ethylene propylene (FEP). These can be applied to bend insensitive fiber already available commercially from OFS, DRAKA, Corning and Sumitomo. This is attractive since it takes COTS fiber and makes it kink and bend insensitive, moisture resistance, chemical resistant and exhibit high tensile strength. The cable has been tested to be impact resistant, kink resistant, and passes temperature cycling test.