Pigtails for use in terminal box, connect the fiber optic cable through the terminal box coupler (adapter) to connect pigtails and fiber patch cables. Fiber Optic Patch Cable: Its two ends are both active joints. Get the wrong connector type, the wrong polish, or skip proper fusion splicing technique—and you're looking at elevated signal loss, increased back reflection, and a. The fiber optic pigtail is a short terminated optical fiber with a connector on one end, used to facilitate easy connections between fiber optic cables and various devices. This article will show you what a fiber optic pigtail is. Align and fuse the pigtail fiber with the main. The most efficient way to terminate a fiber run is by using a pigtail.