Tag Archives: 1000BASE-LX

The Basics of 1000BASE-SX and 1000BASE-LX SFP

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Gigabit Ethernet has been regarded as a huge breakthrough of 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. 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 in the market. Today’s topic will be a brief introduction to 1000BASE-LX and 1000BASE-SX SFP transceivers.

1000BASE in these terms refers to a Gigabit Ethernet connection that uses the unfiltered cable for transmission. “X” means 4B/5B block coding for Fast Ethernet or 8B/10B block coding for Gigabit Ethernet. “L” means long-range single- or multi-mode optical cable (100 m to 10 km). “S” means short-range multi-mode optical cable (less than 100 m).

1000BASE-SX
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 shown in table 1.

1000Base-SX standard

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 that operates over a wavelength of 1310nm for 10 km.

1000BASE-LX SFP

Difference Between LX, LH and LX/LH
Many vendors use both LH and LX/LH for certain SFP modules, this SFP type is similar with the other SFPs in basic working principle and size. However, LH and LX/LH aren’t a Gigabit Ethernet standard and are compatible with 1000BASE-LX standard. 1000BASE-LH SFP operates a distance up to 70km over single-mode fiber. For example, Cisco MGBLH1 1000BASE-LH SFP covers a link length of 40km that make itself perfect for long-reach application. 1000BASE-LX/LH 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. In addition, when used over legacy multimode fiber type, the transmitter should be coupled through a mode conditioning patch cable.

Conclusion
1000BASE SFP transceiver is the most commonly used component for Gigabit Ethernet application. With so many types available in the market, careful notice should be given to the range of differences, both in distance and price of multimode and single-mode fiber optics. Fiberstore offers a large amount of in-stock 1000BASE SFP transceivers which are compatible for Cisco, Juniper, Dell, Finisar, Brocade, or Netgear in various options. If you have any requirement of our products, please send your request to us.

Related Article: Compatible SFP for Cisco 2960 Series Switches

Do You Know About Mode Conditioning Patch Cord?

The great demand for increased bandwidth has prompted the release of the 802.3z standard (IEEE) for Gigabit Ethernet over optical fiber. As we all know, 1000BASE-LX transceiver modules can only operate on single-mode fibers. However, this may pose a problem if an existing fiber network utilizes multimode fibers. When a single-mode fiber is launched into a multimode fiber, a phenomenon known as Differential Mode Delay (DMD) will appear. This effect can cause multiple signals to be generated which may confuse the receiver and produce errors. To solve this problem, a mode conditioning patch cord is needed. In this article, some knowledge of mode conditioning patch cords will be introduced.

What Is a Mode Conditioning Patch Cord?

A mode conditioning patch cord is a duplex multimode cord that has a small length of single-mode fiber at the start of the transmission length. The basic principle behind the cord is that you launch your laser into the small section of single-mode fiber, then the other end of the single-mode fiber is coupled to multimode section of the cable with the core offset from the center of the multimode fiber (see diagram below).

mode conditioning patch cord

This offset point creates a launch that is similar to typical multimode LED launches. By using an offset between the single-mode fiber and the multimode fiber, mode conditioning patch cords eliminate DMD and the resulting multiple signals allowing use of 1000BASE-LX over existing multimode fiber cable systems. Therefore, these mode conditioning patch cords allow customers an upgrade of their hardware technology without the costly upgrade of their fiber plant.

Some Tips When Using Mode Conditioning Patch Cord

After learning about some knowledge of mode conditioning patch cords, but do you know how to use it? Then some tips when using mode conditioning cables will be presented.

    • Mode conditioning patch cords are usually used in pairs. Which means that you will need a mode conditioning patch cord at each end to connect the equipment to the cable plant. So these patch cords are usually ordered in numbers. You may see someone only order one patch cord, then it is usually because they keep it as a spare.
    • If your 1000BASE-LX transceiver module is equipped with SC or LC connectors, please be sure to connect the yellow leg (single-mode) of the cable to the transmit side, and the orange leg (multimode) to the receive side of the equipment. The swap of transmit and receive can only be done at the cable plant side. See diagram below.

mode conditioning patch cord

  • Mode conditioning patch cords can only convert single-mode to multimode. If you want to convert multimode to single-mode, then a media converter will be required.
  • Besides, mode conditioning patch cables are used in the 1300nm or 1310nm optical wavelength window, and should not be used for 850nm short wavelength window such as 1000Base-SX.

Conclusion

From the text, we know that mode conditioning patch cords really significantly improve the data signal quality and increase the transmission distance. But when using it, there are also some tips must be kept in mind. Fiberstore offer mode conditioning patch cords in all varieties and combinations of SC, ST, MT-RJ and LC fiber optic connectors. All of the Fiberstore’s mode conditioning patch cords are at high quality and low price. For more information, please visit fs.com.

Are There Any Differences Between LX, LH and LX/LH?

We usually see LX SFP, LH SFP and LX/LH SFP on many websites, and many people show their confusion about them. Whether they are the same or different? If they are dissimilar, what differences between them on earth?

The Commonly Used 1000BASE-X Standards about Ethernet
Ethernet was the result of the research done at Xerox PARC in the early 1970s. Ethernet later evolved into a widely implemented physical and link layer protocol. Fast Ethernet increased speed from 10 to 100 megabits per second (Mbit/s). Gigabit Ethernet was the next iteration, increasing the speed to 1000 Mbit/s. The initial standard for Gigabit Ethernet was produced by the IEEE in June 1998 as IEEE 802.3z, and required optical fiber. 802.3z is commonly referred to as 1000BASE-X, which is used in industry to refer to Gigabit Ethernet transmission over fiber, where options include 1000BASE-SX, 1000BASE-LX, 1000BASE-LX10, 1000BASE-BX10 or the non-standard -EX and -ZX implementation.

Gigabit Ethernet 1000BASE-LX Optical Interface Specifications

1000base-lx/lh SFP1000BASE-LX is a fiber optic Gigabit Ethernet standard specified in IEEE 802.3 Clause 38 which uses a long wavelength laser (1,270–1,355nm). The 1000BASE-LX SFP is specified to work over a distance of up to 5km over single mode fiber and it can also run over all common types of multi mode fiber with a maximum segment length of 550m. For link distances greater than 300m, you must install a mode-conditioning patch cord between the transceiver and the MMF cable on both ends of the link.

1000BASE-LH and 1000BASE-LX/LH Optical Interface Specifications
LH refers to Long Haul. Many vendors use both LH and LX/LH for certain SFP modules, but they aren’t a Gigabit Ethernet standard at all. 1000BASE-LX/LH SFP can achieve a distance up to 10km over single mode fiber. Unlike 1000BASE-LX/LH SFP, 1000BASE-LH SFP operates a distance up to 70km over single mode fiber.

Conclusion
In a word, the 1000BASE-LX, 1000BASE-LH and 1000BASE-LX/LH are all refer to Gigabit Ethernet transmission. Among them, the 1000BASE-LX is a standard, the 1000BASE-LH and 1000BASE-LX/LH just are terms widely used by vendors. Other long haul transmission standards include 1000BASE-LX10, 1000BASE-EX and 1000BASE-ZX. We can see their differences more clearly in the following chart:

Name  Medium wavelength Specified distance
1000BASE-LX/LH 9/125 Single mode fiber 1310nm  10km
1000BASE-LX 62.5/125, 50/125 Multi mode fiber 1310nm 550m
1000BASE-LX10 9/125 Single mode fiber 1310nm 10km
1000BASE-LH 9/125 Single mode fiber 1310nm 25~70km
1000BASE-EX 9/125 Single mode fiber 1310nm 40km
1000BASE-ZX 9/125 Single mode fiber 1550nm 70km

Related Article: Which Patch Cable Should I Choose for My Optical Transceiver?

Mode Conditioning Patch Cord In Gigabit Ethernet

Mode conditioning fiber optic patch cables, also known as conditioned launch fiber cables, are used specifically in Gigabit Ethernet 1000BASE-LX (and 1000Base-LH) applications where the objective is deploying new high-speed 1000BASE-LX routers, switches, or transceivers within existing multimode system backbones. Mode conditioning fiber jumpers are used in the 1300nm or 1310nm optical wavelength window, and should not be used for 850nm short wavelength window such as 1000Base-SX. Also, any attempt to connect 1000Base-LX/LH equipment over short distances of multimode fiber without the use of mode conditioning fiber will result in a high bit error rate, and eventually damage to the device.

The engineers on the standards committee found that DMD can be prevented in 1000BASE-LX links connected to OM1/OM2 multimode fiber cables by slightly off setting the coupling of laser light into the cable. This avoids the beam splitting that can occur in some MMF cables when laser light is lauched into the direct center of the cable. This type of offset signal launch is called mode conditioning. An ouboard mode-conditioning patch cord must be used when an LX port is connected to a MMF fiber link.

The following picture shows the construction of a mode conditioning cable. The cord contains a splice in the middle, in which the single-mode fiber is carefully connected to the multimode fiber with a slight offset from center. This keeps the single-mode laser light from entering the multimode cable at dead center, avoiding any DMD problems.

Mode Conditioning cable

The standard notes that the single-mode end of the mode-conditioning patch cable should be labeled “To Equipment” and the multimode end “To Cable Plant.” To help with identification, the plastic covering of the single-mode fiber connector should be blue and the multimode connectors should all be beige.

A mode-conditioning patch cord should used at each end of the link when connecting 1000BASE-LX equipment to a multimode fiber optic segment. Make sure that the TX porton the equipment is connected to the single-mode portion of the mode-conditioning patch cable. The multimode fiber used in the conditioned lauch cable should match the multimode fiber plant. In other words, if your fiber plant uses OM1 62.5/125 MMF, then that’s the type of fiber that should be used in the conditioned patch cable as well.