Applicability and recommendation of optical reflectometer technology on naval aircrtaft

Fault location identification within the fiber optic systems of naval aircraft currently requires maintenance personnel to break the optical link to insert test equipment. This procedure changes the configuration which often masks the failure and exposes the fiber link to additional contamination and requires significant time for implementation. The proposed solution to this problem is to build optical power monitors and a reflectometer into the fiber optic transceivers. The transmitter's optical power monitor enables identification of the transmitter's health. The reflectometer enables spatial identification of a failure in the interconnecting fibers. The receiver's power monitor, coupled with the results of the transmitter power monitor and reflectometer, enables identification of the receiver's health. This fiber optic Built-in-Test (BIT) equipment could be remotely activated by the aircraft's Diagnostics and Health Monitor (DHM) system and the results reported via the DHM from a simple user input. This capability enables automatic test of all fiber optic links within the aircraft in seconds without any physical changes to any elements of the fiber system. The resulting report would identify failed transmitters, receivers, and the spatial location of failures in the aircraft's interconnecting fiber. Harris Corporation was funded by NAVAIR through Penn State University to study the technical feasibility of implementing such a BIT system and to recommend a technical approach of the optical reflectometer. This paper presents these results.