Strain measurement and tension distribution analysis for inner and outer layers of guidance optical fiber using BOTDA

In the fiber-optic guided weapon system widely used in battlefields, the guidance optical fiber plays a pivotal role, it needs to transmit signal during the high-speed release process of hundreds of meters per second, while the abnormal force on it may cause breakage or transmission failure, affecting the strike effect of the weapon system. In order to improve its tensile strength, a jacket layer is generally added to the outside of the optical fiber. However, there is no method or experimental report on measuring the actual tension distribution between the inner optical fiber and the outer jacket. In response to this urgent problem, this paper proposes a strain measurement and tension distribution analysis scheme for the inner and outer layers of the guidance optical fiber using BOTDA. We build a strain measurement platform with a spatial resolution of 0.2m and an accuracy of ±20με; the strains of the inner and outer layer were measured when loads ranging from 10N to 100N were applied, and the tension distribution relationship of the inner and outer layers is analyzed; the strain performance differences of guidance optical fibers with different specifications and different storage times were compared, and an evaluation method for improving the tensile strength of the guidance optical fiber by the jacket layer is proposed for the first time. This solution can be used to guide the design and improve the reliability of high-speed release of the guidance optical fibers, which is of great significance to the development of fiber-optic guided weapons.