Single-mode fiber sensor based on core-offset splicing

An inter-mode interferometer based on a simple single-mode fiber by core-offset splicing is presented. Through manually adjusting the horizontal displacement and the angle of two sections of core-offset fiber, we can achieve maximum interference spectrum. Then we add a reflector at the end of the last single-mode fiber. This reflector can lead the light to propagate twice in the offset single mode fiber structure so that we can get larger interference intensity, in the experimental process we see a better extinction ratio. The proposed method can find application in strain, temperature and vibration measurements and so on. By measuring the extinction ratio (ER) variation or wavelength shift of the interference pattern in this paper, sensitivity measurement can be achieved. The sensitivity of strain and temperature without reflector is respectively 10.38 (pm/mu epsilon) and 31pm/degrees C. When reflector added, it can increase the sensitivity of the strain and temperature at a certain degree.