Optical fibers developed for sensor applications often exhibit high optical losses. While these losses may be entirely acceptable for the design application, efforts to improve fiber performance still require loss quantification and the identification of optical loss mechanisms. Existing fiber loss characterization techniques (e.g., optical time domain reflectometry) are generally only appropriate for low loss (communication grade) fibers and may give little or no information on loss mechanisms. At the Pacific Northwest Laboratory, techniques have been developed for the characterization of high-loss (tens of dB per meter) optical fibers which allow discrimination between scattering and absorptive losses. Two techniques are presented. In the "differential scattering" method, differential fiber scattering losses are acquired over the length of the fiber to obtain a scattering loss coefficient. This information combined with a conventional total fiber loss measurement (e.g., using the "cut-back" method) allows inference of the absorptive part of the fiber loss. In the second method, "scanning aperture" characteriza-tion, the fiber is scanned by a moving aperture to yield curves of differential and integral scatter intensity versus length. This curve not only provides corroboration of the previously acquired differential scattering data, but also points out high-loss regions in the optical fiber. Both methods will be fully described. Experimental data on representative fibers will be presented.

Date Published: 23 January 1990
PDF: 13 pages
Proc. SPIE 1180, Tests, Measurements, and Characterization of Electro-Optic Devices and Systems, (23 January 1990); doi: 10.1117/12.963456

Published in SPIE Proceedings Vol. 1180:
Tests, Measurements, and Characterization of Electro-Optic Devices and Systems
Shekhar G. Wadekar, Editor(s)