Compatibility of multiplexed optical fiber sensors with optical communications systems onboard military and commercial aircraft

The compatibility of optical fiber time domain (OFTD) sensors with aircraft optical communications systems is discussed. The OFTD sensors are multiplexed using serial and parallel formats that allow three dimensional strain and temperature mapping. The optical fibers used in these sensor arrays are similar, if not identical, to those used in aircraft optical communication data buses. A 100/140 μm core/cladding diameter silica (glass) fiber using a high temperature resistant polyimide protective coating is employed. This multi-mode (MM) fiber format is typical for short-haul local area networks (LANs) used in aircraft. Furthermore, the 100/140 μm optical fiber is compatible with commercially available fiber optic connectors, splices, splitters, and other peripheral hardware. This opens up the possibility for hybrid fiber optic communication/sensor networks either embedded in or attached to aircraft structures. Results are presented on tests performed with prototype sensors using the 100/140 μm MM fiber type. These sensors were embedded in composite laminates that are representative of materials used in advanced technology aircraft. Structural strain was monitored and compared with data gathered through conventional means (strain gages and extensometers). Future applications and possibilities for advanced field trials which combine the OFTD sensor concept with existing fiber optic data buses on aircraft are also proposed