Built-In Test for Fiber Optic Networks Enabled by OTDR

Optical time domain reflectometry (OTDR) is a well-known means of testing a fiber optic cable assembly in optical networks. The OTDR launches a very narrow pulse into the fiber and then records the response of the cable/connector assembly to this pulse. Both reflections and absorption can be observed in the cable, providing the troubleshooter with the information needed to diagnose cable problems. Boeing Phantom Works has developed an OTDR function that eliminates all of these problems. Because it can operate with very low-level optical power, the OTDR function can use the same laser and detector used for communications. The recurring cost of the added hardware is expected to be relatively low and will fit into the standard fiber optic transceiver packages currently in use in military and commercial aerospace applications. Because the OTDR function is built in to the fiber optic transceivers, no connectors need to be demated. As a result of this new network diagnostic technology, a technician will be able to locate a fault down to the box or cable in a matter of minutes and, in the case of a cable harness fault, will be able to locate to within inches the cable fault