SFP 1000BASE-SX Multimode VS. 1000BASE-LX Single-mode
Gigabit Ethernet has been regarded as a huge breakthrough in the telecom industry by offering speeds of up to 100Mbps. Gigabit Ethernet is a standard for transmitting Ethernet frames at a rate of a gigabit per second. Additionally, SFP transceivers are available in different transmitter and receiver types, allowing the user to select the appropriate transceiver for each link to provide the required optical range. There are five physical layer standards for Gigabit Ethernet using optical fiber (1000BASE-X), twisted pair cable (1000BASE-T), or shielded balanced copper cable (1000BASE-CX). 1000BASE-LX and 1000BASE-SX SFP are two common types of optical transceiver modules on the market. Today’s topic will be a brief introduction to 1000BASE-LX and 1000BASE-SX SFP transceivers.
What is SFP 1000BASE-SX?
1000BASE-SX is a fiber optic Gigabit Ethernet standard for operation over multi-mode fiber using 770 to 860 nanometer, near-infrared (NIR) light wavelength. The standard specifies a distance capability between 220 meters and 550 meters. In practice, with good quality fiber, optics, and terminations, 1000BASE-SX will usually work over significantly longer distances. This standard is highly popular for intra-building links in large office buildings, co-location facilities, and carrier neutral internet exchanges. 1000BASE-SX SFP works at 850nm wavelength and is used only for the purpose of the multimode optical fiber with an LC connector. 1000BASE-SX SFP traditional 50 microns of multimode optical fiber link is 550 meters high and 62.5-micron fiber distributed data interface (FDDI) multimode optical fiber is up to 220 meters. Take EX-SFP-1GE-SX as an example, this SX fiber transceiver supports DOM function and the maximum distance of the SX SFP is 550 m. The 1000Base-SX standard supports the multimode fiber distances shown in table 1.
What is SFP 1000BASE-LX?
Specified in IEEE 802.3 Clause 38, 1000BASE-LX is a type of standard for implementing Gigabit Ethernet networks. The “LX” in 1000BASE-LX stands for long wavelength, indicating that this version of Gigabit Ethernet is intended for use with long-wavelength transmissions (1270–1355 nm) over long cable runs of fiber optic cabling. 1000BASE-LX can run over both single mode fiber and multimode fiber with a distance of up to 5 km and 550 m, respectively. For link distances greater than 300 m, the use of a special launch conditioning patch cord may be required. 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 multimode building fiber backbones and single-mode campus backbones. E1MG-LX-OM is Brocade 1000BASE-LX SFP, this LX single-mode transceiver operates over a wavelength of 1310nm for 10 km.
1000BASE-SX SFP VS. 1000BASE-LX SFP
1000BASE-SX is a physical layer specification for Gigabit Ethernet over fiber optic cabling as defined in IEEE 802.3z. The SX systems operate full-duplex with multimode fiber only, using the cheaper 850nm wavelength laser diodes. The maximum distance supported varies between 220 and 550 meters depending on the bandwidth and attenuation of the fiber optic cable used.
As opposed to 1000Base-SX, 1000BASE-LX uses long wavelength laser over both multimode and single-mode fiber. It has a working distance of up to 10 km over single-mode optic fiber, and a maximum length of 550 meters on multimode fiber. So the 1000BASE-LX SFP can operate on standard single-mode fiber optic link spans of up to 10 km, and up to 550 m on any multimode fibers. Arista Networks SFP-1G-LX is 1000BASE-LX SFP transceiver that operates over a wavelength of 1310nm for 10 km on SMF and 550m on MMF.
Single-mode SFP VS. Multimode SFP
SFP modules can be divided into single-mode SFP and multimode SFP modules. For single-mode SFP modules, there are “LX” for 1310nm and “EX” “EZX” for 1550nm. Single-mode fiber SFP is designed to transmit signals over long distances. So the single-mode module works mainly in the 1310nm and 1550nm wavelengths and is mostly used in a long distances transmission environment reaching 2 km, 10 km, 40 km, 60 km, 80 km and 120 km. For example, Cisco GLC-ZX-SM is a single-mode module, which operates over a wavelength of 1550nm for 80 km.
1000BASE-SX is a fiber optic Gigabit Ethernet standard for operation over multi-mode fiber using a 770 to 860 nanometer, near infrared (NIR) light wavelength. The standard specifies a distance capability between 220 meters and 550 meters. In practice, with good quality fiber, optics, and terminations, 1000BASE-SX will usually work over significantly longer distances. This standard is highly popular for intra-building links in large office buildings, co-location facilities and carrier neutral internet exchanges. 1000BASE-SX SFP works at 850nm wavelength and used only for the purposed of the multimode optical fiber with an LC connector. 1000BASE-SX SFP traditional 50 microns of multimode optical fiber link is 550 meters high and 62.5 micron fiber distributed data interface (FDDI) multimode optical fiber is up to 220 meters. Take EX-SFP-1GE-SX as an example, its maximum distance is 550m with DOM support. The 1000Base-SX standard supports the multimode fiber distances.
Single-mode SFP(extraction lever):
- LX – 1310 up to 10km
- EX – 1310 up to 40km
- ZX – 1550 up to 80 km using green ex lever
- EZX – 1550 up to 160 km
- Black color coded bale clasp designates a Multi-mode SFP
- Blue color coded bale clasp designates the 1310nm SFP
Types of Optical Fibers
1000BASE-LX single-mode SFP module will work with single-mode fiber in order to perform both transmission and reception of data. Whereas 1000BASE-SX multimode SFP transceiver will continue to work with multimode fiber, which has a thicker core and allows higher speed at shorter distance.
1000BASE-LX single-mode SFP transceivers are mostly used in long distances (up to 10 km) transmission environment. 1000BASE-SX SFP multimode is only used for short distances (up to 550m), like in small area or within the building.
1000BASE-LX single-mode SFP transport the optical signal for long distance, but there is one signal in the “tunel”. 1000BASE-SX multimode SFP has many optical signal in one “tunel”, the signals may affect each other. So it can transport many kind of optical signals.
1000BASE-SX multimode optics are affected by modal dispersion, because the light rays follow different paths through the fiber and arrive at different times on the other end. This is the main reason the distance on this type of optic is limited. Whereas 1000BASE-LX single-mode optics are affected by wave guide dispersion, caused by the light going down the fiber being wider than the core of the fiber. This allows more control of the path of the photons, but is more affected by micro bends, twists and stress on the fiber.
With 1000BASE-SX SFP multimode versus 1000BASE-LX SFP singlemode, we can actually conclude that the 1000BASE-SX standard was developed to support low cost multimode fiber operating in horizontal and shorter length backbone applications, The 1000BASE-LX standard was developed to support longer-length multimode building fiber backbones and singlemode campus backbones. Gigabit Ethernet fiber optic solution that supports half-duplex and full-duplex transmission at 1Gbps (1000mbps). There are many types of SFP modules on the market, and attention should be paid to the range of differences, including transmission distance, wavelength, cable type, price, etc.