White light interferometer

The Distributed Polarization Crosstalk (X-Talk) Analyzer (PXA-1000) is an enhanced version of a white light interferometer designed to obtain space-resolved stress information by analyzing stress-induced polarization cross-coupling along a length of polarization maintaining (PM) fiber. Its patent-pending optical design eliminates the strong zero-order interference and reduces the multi-coupling interference common in traditional white light interferometers, both of which can cause ghost peaks in the measured signal. The removal of the ghost peaks enables the PXA-1000 to unambiguously identify the magnitudes and locations of actual x-talk peaks, resulting in higher measurement sensitivity, higher dynamic range, and higher spatial measurement accuracy than traditional white light interferometers. The PXA-1000 also enables the use of the PM fiber itself as the sensing medium, eliminating the need to place multiple fiber gratings along the fiber. It can therefore obtain higher spatial resolution of the stress distribution than grating-based systems. Because no discrete sensing elements are required, the system is easy to install and calibrate, making it ideal for monitoring space-resolved structural changes along bridges, tunnels, dams, oil pipes, or buildings. It can also be used as an intrusion detection system, because any mechanical disturbances to the PM fiber will cause polarization coupling.