Fiber bend losses produced by soft and swellable materials for hydrocarbon detection

We present results of measurements of fiber bend loss caused by soft and swellable materials with perturbation periods of 1-20 nun. We used swellable materials that have different moduli of Young. We show that the swell of soft materials causes the pure bend loss that increases when the period rises to 10 nun. We show that the higher the modulus of Young the higher the loss caused by swellable materials. These results may be used to choose suitable materials and construction for assembling a fiber optics sensor based in the bend loss. (C) 2002 Elsevier Science B.V. All rights reserved.