A pigtail fiber is a short optical fiber with a factory-terminated connector on one end and a bare, exposed fiber on the other.

A fiber optic pigtail typically consists of a single, short length of optical fiber, usually between 0.5 meters and 5 meters, depending on the application . One end has a factory-polished connector—commonly LC, SC, or FC types—used to plug into equipment, patch panels, or optical distribution frames. The other end is bare fiber, stripped of its protective jacket, designed to be fusion-spliced or mechanically spliced to a bulk fiber cable in the field . Physical characteristics include:

• Tight-buffered fiber (around 0.9mm diameter) for protection inside enclosures.
• Ceramic ferrule at the connector end, often 1.25mm or 2.5mm, providing precise alignment for low insertion loss and high return loss .
• Flexible, unjacketed bare fiber on the splicing end, which is relatively fragile and must be handled carefully.
• Color-coded jackets or connectors to indicate fiber type (single-mode, multimode, or specialty fibers) and connector polish (UPC or APC) for easy identification . Unlike a patch cord, which has connectors on both ends, a pigtail is single-ended, making it ideal for permanent or semi-permanent installations where fibers from a multi-fiber trunk need to be terminated neatly and reliably . In practical terms, it looks like a short cable with a small connector on one end and a thin, exposed fiber “tail” on the other, ready for splicing into a network.