Theoretical Simulation and Discussion on Fusion Process of Hollow Core Fiber

Abstract

The hole collapse of hollow core fiber fusion is a key difficulty in sensor fabrication. In this paper, the hollow core fiber fusion is theoretically analyzed and optimized. The heat conduction and deformation of fiber are simulated by COMSOL software. The fiber temperature distribution at fusion area are discussed at different fusion time. Then the deformation value and fiber melting time with different heat flux are simulated and discussed. The deformation value and time value both showed decreasing trend with bigger heat flux. Although it is difficult to get zero deformation value, even if at fiber melting temperature, the fusion deformation can be effectively controlled at some scale. For typical 1% hole diameter deformation scale, the heat flux value should be more than 1.00505×107 W/m2. Considering the small contact surface between hollow core fiber and common fiber end, for getting sufficient fusion, we still simulated the required time of 1% deformation scale with different heat flux, which can give us more fusion parameters choice. Fusion can be continued after fiber melting temperature until getting 1% deformation control value, which can supply enough time for good and firm fusion. The time difference between melting temperature and 1% hole diameter deformation is simulated. According to the simulated curves, 1.5×107 W/m2 heat flux, with 0.02436 s time difference, may be a good choice for hollow core fiber fusion by typical parameters. It is interesting that some report showed complete collapse is helpful to improve mode-coupling efficiency. For investigating this situation, the required heat flux and fusion time simulation are also operated and analyzed. The simulation and discussion in this paper gave deep understanding and some reference advice for optimizing hollow core fiber fusion.