Core and Cladding: The body is the thin glass center of the fiber where the light propagates. Their combined structure enables total internal reflection, allowing light to travel down the fiber. Executive Summary: A fiber optic pigtail is one of the most commonly specified yet least understood components in structured cabling. 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. 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.