SfP

SFP stands for Small Form-factor Pluggable, a compact, hot-pluggable optical transceiver used in data communications and telecommunications. An SFP transceiver combines a transmitter and receiver in a small module that plugs into an SFP slot on network devices such as switches, routers, and servers, enabling flexible uplinks and fiber connections without replacing the host hardware.

The physical and electrical interfaces of SFP devices are defined by the SFP MSA and related specifications. The module is designed to fit a standard SFP cage and interfaces via a 20-pin electrical connector to the host device, while the optical interface uses a fiber optic connector (commonly LC) to link to fiber. The optics support various wavelengths depending on fiber: 850 nm for multimode fiber, 1310 nm or 1550 nm for single-mode fiber. Different transceivers are described by short names such as SR (short reach), LR (long reach), LX (long reach on SMF), and EX, and may support CWDM or DWDM as needed.

Data rates and generations have evolved beyond the original 1 Gbit/s SFP. The term SFP is often used for 1 Gbps modules, while SFP+ denotes higher-speed variants suitable for 10 Gbit/s and beyond, and SFP28 refers to 25 Gbit/s implementations. SFP modules are widely used in Ethernet and Fibre Channel implementations. They are designed to be hot-swappable to minimize downtime, and many include digital diagnostic monitoring through an I2C interface per the SFF-8472 standard.