DISTRIBUTED FIBER-OPTIC SENSORS
Optical fibers constitute an exceptional sensing platform. Fibers support long-reach measurements over hundreds of km, they may be embedded within most structures with little effect of functionality, they are immune to electro-magnetic interference, and may be installed in hazardous environments where the use of electrical currents is precluded. In conjunction with proper setups, the propagation of light in fiber can be made sensitive to a broad variety of environmental parameters of interest, such as: temperature, humidity, mechanical strain, external forces, electrical and magnetic fields, presence and concentration of chemical and biological reagents, and more.
Most fiber sensor configurations provide point measurements: they monitor a parameter of interest in a single location, whereas the rest of the fiber serves for connection with test and measurement equipment. In contrast, some sensor classes are distributed. In these sensors, every section of a standard fiber serves as an independent sensing node, and a quantity of interest may be mapped in a spatially-continuous manner.
Our group specializes in distributed fiber sensors that rely on the nonlinear optical propagation effect of stimulated Brillouin scattering (SBS). We have come up with new coding and data analysis schemes that extend the number of resolution points that may be successfully addressed. We have recently reported the analysis of an 8.8 km-long fiber with 2 cm spatial resolution. All 440,000 resolution points were successfully addressed.
• E. Preter, D. Ba, Y. London, Y. Antman, O. Shlomi and A. Zadok, "High-resolution Brillouin optical correlation domain analysis with no spectral scanning," Opt. Express 24, 27253-27267 (2016).
• Y. London, Y. Antman, E. Preter, N. Levanon, and A. Zadok, "Brillouin optical correlation domain analysis addressing 440,000 resolution points," J. Lightwave Technol. 34, 4421-4429 (2016).
• A. Zadok, Y. Antman, N. Primerov, A. Denisov, J. Sancho, and L. Thevenaz, "Random-access distributed fiber sensing," Laser and Photon. Rev. 6, L1-L5 (2012).