Highly stretchable hybrid silica/polymer optical fiber sensors for large-strain and high-temperature application

The large-range and high-sensitivity strain measurement in high-temperature ambiance is a great challenge in engineering applications. Because of the frangibility of the glass material, the traditional optical fiber strain sensors cannot endure a limit strain of 1%. To break through the limit, we propose a hybrid silica/polymer optical fiber sensor. It can endure extraordinarily large strain. The maximum strain of 35% is confirmed by experiments. To achieve high sensitivity and detect a small change in strain, a phase tracking method is used. The sensitivity of the sensor is 28 pm/με which is 28 times larger than that of the traditional FBG sensors. In addition, because of the excellent high-temperature endurance of polyimide (PI) and adhesive, the sensor can survive in the high temperature up to 220 °C. The proposed hybrid silica/polymer optical fiber sensor has potentials to monitor deformation in plastic products, structure health in composite materials, and even strain in biomaterials.