A fusion splicer uses a(n) _____ to join glass fibers together.

A fusion splicer uses an electric arc to join glass fibers together. This process involves aligning the ends of two optical fibers precisely and then applying an electric arc discharge between electrodes. The heat generated by the electric arc melts the glass fibers at their tips, allowing them to fuse together into a continuous piece.

This method is highly effective for creating low-loss connections, as the fused joint typically has similar optical properties to the original fibers. It is widely used in telecommunications and other applications where minimal signal attenuation is crucial. The precision and quality of the splice made using an electric arc make it the preferred choice over mechanical or other types of connectors.

Mechanical connectors, optical couplers, and heat sinks serve different functions and are not suited for the fusion process. Mechanical connectors, for example, rely on physical alignment rather than melting, while optical couplers are designed to merge light from multiple sources without necessarily connecting fibers directly. Heat sinks help manage heat in electronic components but play no role in the splicing of fibers.