SFP module (Small form-factor pluggable) is a compact optical transceiver used in optical communications for telecommunication and knowledge communications applications. SFP transceivers offer a convenient and price effective solution for that adoption in data center, campus, metropolitan area access and ring networks, and storage space networks.

SFP Optical Module Structuer:
SFP module includes Laser (such as the TOSA transmitter and receiver ROSA), circuit board of IC and external accessories, external fittings are shell, base, PCBA, ring, buckle, unlock parts, rubber plug, in order to identify easily generally pull ring color determining the module parameter type.

SFP Transceiver Types:
According to the rates, SFP transceivers are divided into 155M/622M/1.25G/2.125G/4.25G/8G/10G. Included in this, 155M and 1.25G modules are utilized most often. Using the gradually mature of 10G technology, the requirement can also be recleasing.

Based on the wavelength, there are 850nm/1310nm/1550nm/1490nm/1530nm/1610nm SFP transceivers. The wavelength of 850nm SFP is multimode with the transmission distance less than 2KM. While, 1310/1550nm for singlemode with the transmission distance more than 2KM. Furthermore, 850nm/1310nm/1550nm SFP modules are less costly than the others.

You'll easily confused through the naked SFP modules if there is no identification. General manufacturers identify each other by the colour of the pull ring, such as black pull ring for multimode, wavelength of 850nm; blue is wavelength of 1310nm module; yellow is the wavelength of 1550nm module; purple may be the wavelength 1490nm module.

The main difference between Multi-mode and Single-mode SFP modules:
Multi-mode
Almost all of the multimode fiber optic dimensions are 50/125μm or 62.5/125μm, and bandwidth (the data transmission capacity of optical fiber) is usually from 200MHz to 2GHz. The transmission of multimode modules could be as much as 5 km by multimode fiber. Make use of a light emitting diode or laser like a light source. Pull ring or in vitro color As black.

Single-mode
The singlemode fiber dimension is 9-10/125µm, unlimited bandwidth and lower loss compared with the multi-mode optical fiber. Single-mode optical transceivers are widely used for long-distance transmission, sometimes can up to 150-200 km. Using LD or perhaps a narrow spectral type of the LED as a source of light. The pull ring or perhaps in vitro color is blue, yellow or purple.

Differences and connection
Single-mode fiber is affordable, but multimode device similar with single-mode devices are expensive. Singlemode devices typically could be operated in a single-mode optical fiber, may also be operate on a multi-mode fiber, but multi-mode devices only run in a multimode optical fiber.

The 10G module, develops from 300Pin, XENPAK, X2 and XFP, finally attain the signal transmission of 10G with the same size of SFP, and it is called sfp plus transceiver. SFP module meets the requirements of high-density equipment with its miniaturized low-cost advantages. 10G SFP + transceiver, pushed in the 2002 standard, replaced the XFP this year, is just about the 10G mainstream market.