LXvs SX SFP ：What's the difference?

Title: LX vs SX SFP: Delving into the Distinct Differences in Optical Communication Modules

Introduction:

Small Form-factor Pluggable (SFP) optical modules, a modern standard for optical communications, play a crucial role in telecommunications and data communications networks by converting electrical signals into optical signals. Amid myriad variants, two types - short wavelength (SX) and long wavelength (LX) modules, standout. Both modules serve unique applications in a complex network structure, but what truly separates the SX from LX? 

Demystifying SFP Optical Modules:

Before bringing the LX and SX modules into the light, understanding the basis of SFP modules is imperative. SFP optical modules - transceivers developed to add Gigabit capability to network devices, consist of optical transmitters and receivers. Contributing to their reliability and high performance, they support communication across different data rates and distances, while their hot-pluggable nature offers the flexibility of upgrades with ease.

The SX and LX nomenclature relate to the type of laser and cable required for data transmission. Both these variants differentiate based on their transmission rate, transfer distance, cost, and fiber type.
 

The Spectrum of Differences:

SX SFP Optical Modules:

SX modules operate on a short wavelength of 850 nm. The "short" in SX, implies its application for short-range communications. They typically use multimode fiber optics (MMF) for data transmission, allowing multiple light signals to propagate simultaneously. Benefiting from their ability to operate on low-cost MMF, SX modules are economical and effective for connections within the same building or between close geographical locations.

Applying VCSEL (Vertical Cavity Surface Emitting Laser) technology, SX modules impart high performance and lower interference for short-distance transmission. They are optimally designed to handle data rates from 100 Mbps to 4.25 Gbps, with the capacity to transmit over distances up to 550 meters.
 

LX SFP Optical Modules:

On the contrary, LX modules operate on a long wavelength of 1310 nm. Here, the "long" indicates its suitability for long-range communications. They work primarily with single-mode fiber optics (SMF), efficiently transmitting data over greater distances. By result, LX modules are more expensive, due to the cost of SMF and the laser technology required. 

Unlike the SX, the LX uses Fabry-Perot edge-emitting lasers for high-speed, long-distance transmission, delivering superior efficiency over considerably longer distances. LX modules can support data rates up to 1 Gbps and are capable of transmitting over distances stretching up to 10 kilometers. 

Some LX modules, known as Long Reach (LX/LR) SFPs, even employ a mode conditioning patch cable to extend their reach up to 20 kilometers on MMF alongside SMF. Hence, these modules are an optimal choice for connections spanning across different sites or within sprawling data centers.
 

Comparison: Weighing the Benefits and Limitations:

Both LX and SX SFP modules have their unique strengths and limitations. While SX modules support shorter transmission distances, their low cost and ability to operate over readily available MMF make them a desirable choice for data communication within shorter ranges. Conversely, despite the higher costs, LX modules' ability to transmit over far greater distances using either SMF or MMF with a mode conditioning patch cable renders them preferred for network applications with longer reach requirements.
 

Closing Remarks:

Whether to opt for LX or SX SFP modules remains a decision influenced by the specifics of the network in question, namely the required data transmission rate, the distance to be covered, and budget considerations. Understanding the distinctive features and applications of both these optical modules will aid in making the most appropriate selection, conforming to the demands of the network setup. 

One crucial commonality between these two modules is their role in laying the groundwork for efficient, fast, and reliable telecommunications and data communications. Ultimately, the development and continuous advancement in SFP technology reflect our relentless quest for better connectivity and communication, underpinning the growth and progress in the global communications industry.

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 SFPcan 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.
 

What do LX SFP and SX SFP represent respectively?

What is lx SFP?

LX SFP, or Long Wavelength Small Form-factor Pluggable, is a type of transceiver module used in optical communications for both telecommunication and data communications applications. The 'LX' stands for long wavelength, indicating that this type of SFP module operates on a longer wavelength of 1310 nanometers (nm).

LX SFP modules are primarily designed to transmit data over single mode fiber (SMF) cables, which are capable of longer transmission ranges compared to multimode fiber cables. As such, LX SFPs, are well suited for long-distance communication, with a general reach of up to 10 kilometers.

These modules convert electrical signals into optical signals in the transmitter section and convert these incoming optical signals back to electrical signals in the receiver section. LX SFPs usually can support data rates up to 1 gigabit per second (Gbps). 

For even longer transmission distances, a special variant of the LX SFP known as the Long Reach (LX/LR) exists, that can extend transmission distance up to 20 kilometers by using a mode conditioning patch cable.

While LX SFPs can be more expensive due to the cost of the laser technology used and the single mode fiber optic cables, their ability to achieve this long distance data transmission makes them an essential component in applications where data needs to be reliably transmitted over long distances, such as wide area networks, large corporate networks or in data centers.

 

What is SX SFP?

SX SFP, or Short Wavelength Small Form-factor Pluggable, is a type of optical transceiver module used in optical communications for both telecommunication and data communications applications. 'SX' stands for short wavelength, indicating that this SFP module operates on a short wavelength of 850 nanometers (nm).

SX SFP modules are specifically designed to transmit data over multimode fiber (MMF) cables. Unlike single-mode fiber used with LX SFPs, multimode fibers have a larger core diameter, which allows multiple light signals to propagate simultaneously. As a result, SX SFPs are designed for short-distance communication, typically achieving a maximum reach of up to 550 meters.

SX SFP modules also convert electrical signals into optical signals for transmission and reverse the process at the receiver end. They use VCSEL (Vertical Cavity Surface Emitting Laser) technology, which provides high-speed data transmission with low interference over these short distances.

Despite their shorter reach, SX SFP modules have the advantages of being more economical and capable of handling substantial data transfer rates, ranging from 100 Mbps to 4.25 Gbps, making them an excellent choice for applications like local area networks (LANs), intra-building links, and short-distance connections.

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-SX SFP Multimode VS. 1000BASE-LX SFP Single-mode

• Standard

SX stands for short wavelength. The standard specifies a distance capability between 220 meters and 550 meters. 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 – 1355nm) 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 10 km and 550 m, respectively.

• 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 work with multimode fiber, which has a thicker core and allows higher speed at shorter distance.

• Transmission 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.

• Wavelength

1000BASE-LX single-mode SFP works in 1310nm, whereas 1000BASE-SX SFP multimode works in 850nm.

• Transmission Medium

1000BASE-LX single-mode SFP transport the optical signal for long distance, but there is only 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.

• Dispersion

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.

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.