Engineering Commons^™

Modal Interference Techniques For Strain Detection In Few-Mode Optical Fibers, Bradley D. Duncan

Electro-Optics and Photonics Faculty Publications

Interference between the modes of an optical fiber results in specific intensity patterns which can be modulated as a function of disturbances in the optical fiber system. These modulation effects are a direct result of the difference in propagation constants of the constituent modes. In this presentation it is shown how the modulated intensity patterns created by the interference of specific mode groups in few-mode optical fibers (V < 5.0) can be used to detect strain. A detailed discussion of the modal phenomena responsible for the observed strain induced pattern modulation is given and it is shown that strain detection sensitivities on the order of 10-9 can be expected. Data taken during the evaluation of an actual experimental strain detection system based on the developed theory is also presented.

Technical Report El-88-18: Reliability Of The Federally Owned Water Main System, Donald V. Chase, Lindell Ormsbee, Thomas M. Walski

Civil and Environmental Engineering and Engineering Mechanics Faculty Publications

The reliability of the Federally Owned Water Main (FOWM) system was examined, and recommendations to improve system reliability are made. The existing FOWM system is very dependent upon three different pipe links.

The first and most important link is the Francis Scott Key Bridge river crossing. This link carries the entire FOWM supply, and if taken out of service, an alternate means of supply must be used. At present, the only alternate source of supply is through interconnections with the adjacent Arlington County, Virginia, system.

The second vital link is the 30-in. steel main which extends from the Key Bridge …