SFP and SFP+ Transceivers for Networking Use

Nowadays, it seems to be a commonplace that fiber optic systems have been deployed as the main means of data transmission in this modern work. And to better meet the increasing demands for internet protocol (IP)-based services, including voice, video, and data in highly reliable fiber optic communication, countless fiber optic products have been brought to the market, like fiber optic transceivers. These transceiver modules are designed by integrating electro-optical converters in many forms, like small form-factor pluggable (SFP) and small form-factor pluggable plus (SFP+). Both SFP and SFP+ transceiver modules offer a convenient and cost effective solution for the adoption of Gigabit Ethernet (GbE), 10GbE and Fibre Channel (FC) in data center, campus, metropolitan area access and ring networks, and storage area networks. In a word, they are widely used in networking architecture. But have you obtained a deep understanding about them?

SFP Modules

A transceiver includes both transmitter and receiver in a single module. The transmitter and the receiver of the SFP transceiver function independently for bidirectional communication. The transmitter takes an electrical input and converts it to an optical output from a laser diode or LED. The light from the transmitter is coupled into the fiber with a connector and is transmitted through the fiber optic cable plant. The light from the end of the fiber is coupled to a receiver where a detector converts the light into an electrical signal which is then conditioned properly for use by the receiving equipment.

Compatible with SFP Multi-Source Agreement (MSA) and SFF-8472, SFP modules are able to work through single-mode fibers (SMFs), and multi-mode fibers (MMFs), with the distance reach ranging from less than 550m over MMFs to 70km over SMFs. Take 1000BASE-SX SFPs (eg. MGBSX1) for example, this port type is standardized to operate over MMF for the possible 550m reach. SFP transceivers are also available with a copper cable interface to connect to unshielded twisted pair networking cable. The copper transceivers can be installed into optical SFP slots, enabling an optical Ethernet port (1000BASE-X) to be converted into a copper Ethernet port (1000BASE-T) either in the field or in production.

SFP transceivers are used in optical communications for both telecommunication and data communications applications, which are designed to support SONET/SDH, GbE, FC and other communications standards.

SFP+ Modules

To fit the growing lusts for the transmission capacity and bandwidth, 10GbE products are brought to the market, including SFP+ and XFP, with the former being the most popular 10G transceiver type currently. As the upgraded version of the SFP, SFP+ transceivers are widely used for 10Gbit/s data transmission applications, like data center, enterprise wiring closet, and service provider transport applications.

Designed with higher data rate and new industrial standards, SFP+ has a more compact size with the former 10G X2 and Xenpak transceivers, more suitable for density installations because of its greater ability. 10 gig SFP is ideally suited for datacom and storage area network (SAN/NAS) applications based on the IEEE 802.3ae and Fiber Channel standards, Fiber Channel 10G, 8.5G, 4.25G, 2.125G, 1.0625G, 10G BASE- SW/SR/LR/ER, 1000BASE-SX Ethernet.

SFP+ transceiver electrical interface is compliant to SFI electrical specifications. The transmitter input and receiver output impedance is 100 Ohms differential. Data lines are internally AC coupled. The SFP plus module provides differential termination and reduce differential to common mode conversion for quality signal termination and low EMI. SFI typically operates over 200mm of improved FR4 material or up to about 150mmof standard FR4 with one connector.

SFP/SFP+ DDM Function

Most of the SFP and SFP+ modules are built with digital diagnostic monitoring (DDM) function, or called digital optical monitoring (DOM) function according to the industry standard MSA (Multi-Source Agreement) SFF-8472. This function can provide component monitoring on transceiver applications in details, such as the real-time parameters of the fiber optic transceivers, like optical input/output power, temperature, laser bias current, and transceiver supply voltage, etc. Besides, DDM interface includes a system of alarm and warning flags which alert the host system when particular operating parameters are outside of a factory set normal operating. Thus, DDM interface can also enable the end user with the capabilities of fault isolation and failure prediction.

Summary

It's obvious that both SFP and SFP+ transceiver modules have been considered as the the instrumental tools in fiber optic systems. They interface a network device motherboard (for a switch, router, media converter or similar device) to a fiber optic or copper networking cable, serving as high-speed pluggable solutions. As an outstanding fiber optic product supplier, Fiberstore offers many SFP and SFP+ modules, which are quality-assured and severely checked for compatibility with devices from some major brands in this industry, like Cisco, Dell, Brocade, and so on. When you need to purchase SFP and SFP+ transceivers for your networking use in future, Fiberstore is a good choice, because of its really low prices and high quality.