Fusion splicers are essential for creating low-loss, high-performance fiber optic connections in telecom, FTTH, and data center applications. The best splicers offer core alignment, fast splice times, durable designs, and smart features like cloud syncing and automated calibration. Top-rated models. The ultimate solution for fast and precise fusion splicing. The automatic intelligent fusion splicer. Overview: A fiber fusion splicer is a device used to join two optical fibers end-to-end using an electric arc.