The XFP (10 gigabit small form-factor pluggable) is a standard for transceivers for high-speed computer network and telecommunication links that use optical fiber. It was defined by an industry group in 2002, along with its interface to other electrical components, which is called XFI.
XFP is a slightly larger form factor than the popular small form-factor pluggable transceiver, SFP and SFP+.