New test method for determining the water sensitivity of optical fiber coatings

Humidity-insensitive optical fibers for distributed sensing applications

“…The first observation is that all fibers have a completely negligible response to RH when compared with the polyimide-coated fiber. This RH insensitivity might be explained by the different DWS of polymer coatings [13]. The DWS parameter depends on the ability of porous material, such as polymers, to absorb water molecules, and it turns out to be smaller for the polymer Desolite DS 3471-3-14 than for other kinds of secondary coatings (Information provided by the manufacturer -on 150 µm films: weight change −2%; extractable −1%).…”

“…The first one is based on a novel optical fiber with a single layer of a specific acrylate coating, the Desolite DS3471-3-14, that combines the properties of soft and hard coating, meaning that the fiber is significantly mitigating microbending and, simultaneously, it is mechanically protected. The choice of this polymer coating is due to its low dynamic water sensitivity (DWS), enabling increased fiber drawing speeds and offering improved humidity resistance [13]. Several Desolite-coated fibers with different coating thicknesses were produced to fully investigate the RH effect at temperatures from −20 • C to 50 • C, using a chirped-pulse phase-sensitive optical time domain reflectometer (CP-φ-OTDR) interrogator [14].…”