Numerical study on the internal stress of optical fiber connector in the aerospace wide temperature range

Abstract

Aiming at the problem of fiber break failure of optical fiber connector used in aerospace wide temperature range environment, the finite element simulation model is established based on the mature optical fiber contact structure. The influence of some typical factors, such as expansion coefficient of fiber adhesive, filling amount of adhesive, and material of metal tailstock, on the internal stress of optical fiber contact parts is analyzed quantitatively at extreme temperature of +100℃ and -100℃. It is found that the axial force exerted on the fiber by the metal tailstock and ceramic ferrule due to high and low temperature expansion and contraction is the main source of the internal stress. The junction area of ceramic ferrule cone and straight section is the most prone to fiber breakage. The difference between the maximum axial internal stress of optical fiber at +100℃ and -100℃ is regarded as the index to evaluate the internal stress of optical fiber. The metal tailstock with low expansion coefficient can significantly reduce the internal stress of optical fiber. Compared with aluminum alloy tailstock, the maximum stress difference of Kovar alloy tailstock can be reduced by 51.5%. The internal stress of optical fiber can be reduced to a certain extent by appropriately reducing the filling amount of optical fiber adhesive between ceramic core and metal tailstock and the expansion coefficient of optical fiber adhesive. The results show that the maximum stress difference can be reduced by 11.4% if only the conical region is filled. When the thermal expansion coefficient of optical fiber adhesive decreases from 60e-6/℃ to 30e-6/℃, the maximum stress difference declines by 8.9%. This paper can provide a reference for improving the design of optical fiber connector for aerospace wide temperature range.