Fiber optic pigtail is used is to link the fiber optic cable with fiber optic equipment. 
The fiber optic pigtail with connector side is used to link the equipment, while the other side of the pigtail is melted together with the fiber cable, by melting together the fiber glasses, it can reach a minimum ion loss. 

Features:
Low ion loss
High return loss
Excellent mechanical endurance
Good in repeatability and exchangeability
SC, FC, LC, ST ... optional 
Single mode or multimode 

Application:
Telecommunications
FTTX
CATV
Optical communication system