Category Archives: 1000BASE-LX

The Basics of 1000BASE-LX

In computer networking, Gigabit Ethernet is a term describing various technologies for transmitting Ethernet frames at a rate of a gigabit per second, as defined by the IEEE 802.3-2008 standard. As a type of wiring for Gigabit Ethernet, you may see 1000BASE-LX on an SFP transceiver, what does 1000BASE-LX mean? And how does 1000BASE-LX work? Answers will be given in the following text.

1000BASE-LX Definition

1000BASE-LX, a type of standard for implementing Gigabit Ethernet networks, is specified in IEEE 802.3 Clause 38. The “LX” in 1000BASE-LX stands for long wavelength, indicating that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions over long cable runs of fiber optic cabling. 1000BASE-LX uses a long wavelength laser (1270–1355 nm), and a maximum RMS (root mean square) spectral width of 4 nm. The letter “X” indicates that 8B/10B signal encoding technique is used.

How 1000BASE-LX Works

1000BASE-LX can run over both single mode fiber and multi-mode fiber. 1000BASE-LX is specified to work over a distance of up to 5 km over 10 µm single-mode fiber. 1000BASE-LX uses 1300 or 1310nm single mode fiber and laser. Its specification says the maximum operation length is 5km. But manufacturers often guarantee over 10km working length. 1000BASE-LX can also run over all common types of multi-mode fiber. The modal bandwidth for the MMF options ranges from 400 MHz/km to 500 MHz/km, and maximum distance is 550 meters. For link distances greater than 300 m, the use of a special launch conditioning patch cord may be required. This launches the laser at a precise offset from the center of the fiber which causes it to spread across the diameter of the fiber core, reducing the effect known as differential mode delay which occurs when the laser couples onto only a small number of available modes in multi-mode fiber. 1000BASE-LX is intended mainly for connecting high-speed hubs, Ethernet switches, and routers together in different wiring closets or buildings using long cabling runs, and developed to support longer-length multi-mode building fiber backbones and single mode campus backbones. Careful notice should be given to the range of differences, both in distance and price of multi-mode and single-mode fiber optics.

1000BASE-LX SFP Transceivers

1000 BASE-LX is the long wavelength implementation of a similar transceiver that can obviously span a further distance. 1000BASE-SX SFP transceiver module is compatible with the IEEE 802.3z standard and can use both 62.5 and 50 micron multi-mode fiber, as well as single-mode fiber optic cables, with distances of 440m, 550m and 5km respectively. 1000BASE-LX SFP transceivers are available with a variety of transmitter and receiver types, allowing users to select the appropriate one for each link to provide the required optical reach, depending on the customer application and distance capability required. Each optical interface operates and is managed like a fixed port but gives the customer flexibility to hot-swap or interchange to different optical module types. The following is a picture of 1000BASE-LX SFP transceiver.


Fiberstore offers a wide range of 1000BASE-LX SFP transceivers branded by many famous companies, like Cisco, Juniper, and HP. Those optical transceivers, such as J4859A and JD119B branded by HP, Cisco GLC-LH-SM and Cisco MGBLX1, EX-SFP-1GE-LX branded by Juniper, are able to fulfill enterprises, service providers, and telecommunication operators to meet their needs.