Fiber optic round to square pigtail

A round-to-square fiber optic pigtail typically features an FC connector (round) on one end and an SC connector (square) on the other, allowing seamless connection between ODF ports and device optical interfaces.

Overview

A fiber optic pigtail is a short length of optical fiber with a factory-terminated connector on one end and a bare fiber on the other, designed for splicing into a fiber optic cable in the field. The round-to-square pigtail, commonly FC-SC, connects a round FC interface (often used in ODF boxes) to a square SC interface (used on devices or optical ports),. This configuration was widely used in early SBS, Optix, and Huawei OSN series equipment, as well as ZTE S series and Lucent wavelength division devices.

Connector TypesFC (round): Screw-type connector, typically used for stable connections in ODFs or patch panels.

S

C (square): Push-pull connector, commonly used on optical devices and boards. Other variations: FC-FC (round-to-round), SC-SC (square-to-square), SC-LC (square-to-small square) for different network requirements. ApplicationsODF Termination: FC end plugs into the optical distribution frame, while the SC end connects to the device port.

Device Interfacing: Enables legacy equipment with FC ports to connect to modern SC-based devices. Splicing: The bare fiber end is fusion or mechanically spliced to the incoming fiber cable, ensuring low insertion loss and high return loss.

Installation Considerations

Ensure the correct connector type and polish type (UPC or APC) to maintain signal integrity. Avoid bending or stressing the fiber during installation to prevent signal loss or network failure. Multi-fiber pigtails may use color-coded fibers for easy identification in high-density ODF or data center environments.

SummaryRound-to-square fiber optic pigtails like FC-SC provide a reliable solution for connecting legacy round FC ports to modern square SC interfaces, combining factory-grade connector quality with field splicing flexibility. Proper selection and installation are critical to ensure low-loss, stable optical connections in both enterprise and telecom networks.