Small form-factor pluggable is the full name of SFP, a prevailing type of fiber optic transceivers in the market. The transceiver can be simply regarded as the upgraded version of the GBIC module. SFP module is the half size of GBIC, but the numbers of ports configured on the same panels are double. Because the small-factor pluggable transceiver is the same function with GBIC, SFP transceivers is also called as mini-GBIC. By placing the CDR and electrical dispersion compensation outside the modules, SFP transceiver modules greatly compressed the size and power consumptions.
SFP Standard
SFP transceiver is regulated by a competition the Multilateral Agreement (MSA) between the manufacturers. The SFP is designed according to GBIC interface, allowing ratio the GBIC greater port density (the motherboard edge of the number of transceivers per inch), the SFP is also known as “mini-GBICs”. Compared with this small package transceivers (SFF transceiver), which is smaller than the SFP, but the SFF is soldered to the motherboard as a pin through-hole device, but not plugged into the edge.
Types
SFP transceivers have a variety of different transmission and receiving type, the user can select the appropriate transceiver for each link, to provide the optical performance can be achieved based on the available fiber type (such as a multimode fiber or single mode fiber). Optical SFP modules available are generally divided into the following categories:
>SX – 850 nm, for a maximum of 550 m at 1.25 Gbit/s (gigabit Ethernet) or 150m at 4.25 Gbit/s (Fibre Channel)
>LX – 1310 nm, for distances up to 10 km
>EX – 1310 nm, for distances up to 40 km
>ZX – 1550 nm, for distances up to 80 km, with green extraction lever (see GLC-ZX-SM1)
>EZX – 1550 nm, for distances up to 160 km
>BX – 1490 nm/1310 nm, Single Fiber Bi-Directional Gigabit SFP Transceivers, paired as BS-U and BS-D for Uplink and Downlink respectively, also for distancesup to 10 km.Variations of bidirectional SFPs are also manufactured which use 1550 nm in one direction
>1550 nm 40 km (XD), 80 km (ZX), 120 km (EX or EZX)
>SFSW – Single Fiber Single Wavelength transceivers, for bi-directional traffic on a single fiber. Coupled with CWDM, these double the traffic density of fiberlinks
>CWDM and DWDM transceivers at various wavelengths achieving various maximum distances for copper twisted pair cabling
>1000BASE-T – these modules incorporate significant interface circuitry[11] and can only be used for gigabit Ethernet, as that is the interface they implement. Theyare not compatible with (or rather: do not have equivalents for) Fibre channel or SONET
