Getting to Know the SFP Transceiver
A compact, hot-pluggable optical transceiver, the Small Form-Factor pluggable (SFP) transceiver is used in optical communications for both telecommunication and data communications applications. SFP is the interface between a network device mother board and a fiber optic or copper cable network cable.
The SFP transceiver is capable of supporting Gigabit Ethernet, Fiber Channel, SONET, and a number of other communications standards. In the near future, SFP is going to expand to SFP+ for your information. Data rate at 10 Gbit/s will be feasible, including 8 Gigabit Fiber Channel at that time. Compared to Xenpac or XFP type of modules which have all of their circuitry inside, an SFP+ module leaves some of its circuitry to be implemented on the host board.
The SFP transceiver has an immense variation available, each with different transmitter or receivers. This allows the user to configure and customize the transceiver to get the proper optical reach with either a multi-node fiber or single-node fiber type. Moreover, the optical SFP module comes in four categories; these are the SX (850nm), LX (1310nm) and ZX (1550nm) and DWDM. All f them have an interface of a copper cable which allows a host device to communicate via USTP (unshielded twisted-pair) network cable. There are also available a CWDM and single-node bi-directional fiber optic cables which are 1310/1490nm upstream and downstream.
Commercially available, the SFP transceiver has the capability transfer rates of up to 4.25 Gbit/s. A form factor which is practically similar to the SFP type, the XFP increases this amount by nearly three times, at 10 Gbit/s. The SFP transceiver is specified and made compatible via a multi-source agreement (MSA) between manufacturers, so that different users who may use equipment from different manufacturers and providers can work effectively and smoothly without worrying about errors and inconveniences.
The GBIC interface is the pioneer to the SFP, hence it’s nicknamed as mini-GBIC. On the other hand, the SFP allows greater port density (number of transceivers per inch along the edge of a mother board) than the GBIC. There is also the related Small Form-Factor (SFF) transceiver which is about the same size as the SFP. Rather than plugged into an edge-card socket, it is directly attached to the mother board as a pin through-hole device.
The modern optical SFP transceiver supports digital diagnostics monitoring (DDM) or digital optical monitoring (DOM) functions according according to the industry standard of the SFF-8472 MSA. As a result of this feature, the end user has the ability to constantly monitor real-time parameters of the SFP, like optical input/outp power, supply voltage and laser bias current.
Those being said, it’s good to know that the SFP transceiver is a very popular format that is recommended by quite a number of fiber optic component providers. These companies carry SFP transceivers for all Cisco devices together with transceiver modules for many other manufacturers. So, if you need technology solutions for your networking applications, you now what to look for.