Determine the required length of the pigtail based on the distance between the termination point and the optical equipment it needs to connect to. A fiber pigtail is a short length of optical fiber that comes with a high-quality, factory-polished connector already installed on one end, leaving a length of exposed glass on the other. The connector end is polished and tested under factory conditions, ensuring low insertion loss and high return loss. Compared with quick termination or epoxy and polish connections placed on the field. How to Classify Different Types of Fiber Pigtails? Fiber optic pigtails come in several types. Another classification is by fiber type, which includes single-mode.