The effect of fusion current on thermally diffused expanded core of splicing ultra-low loss fiber and traditional single-mode fiber

Ultra-low loss (ULL) optical fiber is already being used at high altitude in optical communication due to the stable performance in long haul links. Whereas, traditional single-mode optical fiber (SMF) is still used in most general areas since the high price of ULL fiber. Accordingly, there will be an increasing number of junctions between SMF and ULL fibers. The main contents of this work are to study the influence of fusion current on the splice loss caused by thermally diffused expanded core (TEC) of splicing SMF and ULL fibers, and the variations on the diffusion of core dopants and fusion time are also taken into account. Furthermore, the analysis was verified by experiment and simulation. The results illustrate that the changes in fusion current will cause varying degrees of changes in the core and lead to different splice losses due to diffusion, which plays a guidance role in the current calibration of fusion splicer in the future when splicing SMF and ULL fibers. The significance of this work is to reduce the splice loss of SMF and ULL fibers. If the method is applied in a modern fusion splicer, the splice loss of SMF and ULL fibers will be deduced further.