Strain Measurement in Optical Fiber Cable Using Resistance Wire

A resistance wire method is proposed for measuring the longitudinal strain in the glass fiber in an optical cable. In this method, the strain is evaluated by measuring the resistance change of a wire coated with the same material as the glass fiber. It is confirmed that the resistance change rate Δ R / R is proportional to the strain. An optical cable containing both a coated resistance wire and coated fibers was manufactured, and the strain in the cable was measured under tension, bending and vibration. The results are useful for the mechanical design of fiber cable, and the resistance wire method was found to be a simple and useful method of estimating the strain in the fibers inside such a cable.