Effect of Graded-Index Optical Fiber Structure for Sensor Systems using Changes in Radius of Curvature

An optical fiber sensor system using the radius of curvature changes has been proposed.The system can be laid on the face of a target building construction.Experiments on the proposed technique showed that the graded-index polymer optical fiber (GI-POF) had sensitivity to radius of curvature changes and the advantage of mechanical flexibility suitable for sensing a small radius of curvature.Optical losses by changing the radius of curvature in the graded-index optical fiber have been calculated with either simple methods that lack sufficient accuracy or others that require a large capability to calculate.A calculation algorithm that allows the quantitative evaluation of optical losses in bending fiber by a computer with a reasonable performance has been invented, and it has been adopted to a newly developed simulator.The simulation result was comparable to experimental data in the range of 2 dB, in which the radius of curvature is several mm.