Damage of Optical Fibers Under Wet Environments.

Besides signal transmission for telecommunications, fibers are used in an increasing number of devices. A number of applications relate to devices exposed to severe wet environment (hot water, chemical attacks...). It is the case for the sensors used in nuclear plants, high energy physics or plasmas devices. However, reliability issues must be addressed for optical fiber sensors operating under severe conditions such as harsh chemical solutions. The purpose of this work is to study the mechanical behavior and aging of fibers exposed to hot water action, to hydrofluoric acid vapours (HF) and to tetramethoxysilane (TMOS) for different durations. Dynamic fatigue tests were implemented using a two-point bending testing device or tensile test set-up. Standard fibers tested immediately after exposure show a broader distribution of fiber strength accompanied by the drastic decrease of the failure stress. In some particular cases, the gain compared to as received fibers can be positive. Polymer reacts with different wet environments, which induces viscosity changes. This is consistent with SEM observations. [ABSTRACT FROM AUTHOR]