A fiber optic pigtail is a short length of optical fiber —typically 0. 5m to 2m—that has a factory-terminated connector on one end and bare fiber on the other end. 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. ■ What is a fiber optic pigtail cable? A pigtail fiber indicates a short length of optical fiber cable that has a pigtail connector (for example, SC, FC, ST, LC, etc. The other side of the pigtail is open and is connected to a fiber optic cable.