Differences of SFP, GBIC, XFP and SFP Plus

A transceiver is a device composed of optoelectronic devices, functional circuitry and optical interface. The transmitter and receivers are combined and share common circuitry or a single housing. When no circuitry is common between transmit and receive functions, the device is a transmitter-receiver. Technically, transceivers must combine a significant amount of the transmitter and receiver handling circuitry just like transponders, transverters and repeaters. In the transmitter section, a certain bit rate signal after processing by the internal driver chi promote the LD or LED to emit a corresponding rate of the modulated optical signal, the automatic control circuit with an internal optical power, so that the optical signal output power is kept stable. In the receiver section, the input signal with a certain bit rate is converted into an electric signal by a light detection diode and output a corresponding bit rate after preamplifier, which is generally PECL.

SFP and GBIC Transceivers
GBIC (Gigabit Interface Converter) is a hot-swappable Gigabit Interface optical module with SC connector. A gigabit interface converter (GBIC) is a standard for transceivers, commonly used with Gigabit Ethernet and fiber channel. GBIC module is hot pluggable, this feature allows a suitably designed enclosure to be changed from one type of external interface to another simply by plugging in a GBIC having the alternative external interface. SFP is also called mini-GBIC, SFP module is the abbreviation of Small Form Pluggable. It is half the volume of GBIC and can be configured double number of ports on the same panel. Other basic functions is the almost the same with the GBIC.

SFP and SFP Plus
The main difference between SFP and SFP Plus is that the SFP+ is used in Gigabit Ethernet applications while SFP is for 100Bse or 1000Base applications. SFP+ transceivers use the same dimensions of pluggable transceivers in the 10Gbs Ethernet and 8.5Gbs fiber channel with SFP and SFP comply with standards of IEEE802.3 and SFF-8472.

SFP Plus and XFP
SFP plus and XFP are both 10G transceivers, and share the same features with other 10G transceivers. The main difference between them is SFP+ is more compact sized than XFP. The smaller SFP+ transfer the modulation functions, serial/deserializer, MAC, clock and data recovery (CDR) and EDC functions from the module to the motherboard on the card. XFP comply protocol of XFP MSA while SFP plus comply with IEEE802.3, SFF-8431, SFF-8432.

The fiber optic transceivers, as the core of optoelectronic device in the WAN, MAN or LAN application, have also developed various types along with the increasing in complexity. 10G transceivers have experienced developments from 300Pin, XENPAK, X2, XFP and finally realized using the same sized with SFP to transmit 10G signals, what is SFP+. SFP, with its advantages of miniaturized and low-cost, meet the demand of high-density fiber transceivers, and now has replaced the XFP and becomes the main stream of 10G transceivers markets.