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In 1.25 Gig Ethernet optical transceiver modules, although LX and LR often have similar actual transmission distances on single mode fibers, they represent different technical standards, application environments, and typical characteristics. Here are the specific differences:
Definition&Standard
- LX (Long Wavelength): According to the IEEE 802.3 standard, it refers to a “long wavelength” fiber optic receiver module. It is mainly designed to operate at a wavelength of 1310nm and is primarily used for single mode optical fibers.
- LR (Long Reach): stands for “long distance”, indicating that the fiber optic receiver module supports longer transmission distances on single mode fiber, commonly used in 10Gbe SFP modules, but also mentioned in some high-speed 1G specifications.
Transmission Distance
- 1G LX: The typical transmission distance is 10 km (up to 25 km on single-mode fiber).
- SFP 1G LR: In 10G scenarios, it refers to 10 km, but in 1G scenarios, it usually refers to single mode transmission of 10 km, just like LX.
Wavelength and Fiber Type
- 1G LX: Uses a wavelength of 1310nm, typically using SMF OS2. However, 1GE SFP LX transceiver module usually have good compatibility and can also operate on multimode fiber (MMF) through mode conditioning patch cords.
- SFP 1G LR: also uses a wavelength of 1310nm and focuses on single-mode fiber transmission.
Key Application Scenarios
- 1G LX: Widely used in enterprise networks, local area networks (LANs), and telecommunications fields, suitable for medium distance transmission.
- 1G LR: In contrast, LR definition is usually more closely related to 10G Ethernet (10GBASE-LR), and if used for 1G, it tends to refer to single-mode long-distance applications.
Conclusion
In 1GB Ethernet optical transceiver module series, LX is the most common Gigabit SFP module for single mode fiber. If you need to find a 1G single mode 10km module, it is usually labeled as SFP-1.25G-LX. LR appears more frequently in the 10G specification.
| Model | SFP LG LX C Transceiver | SFP 10G LR C Transceiver |
| Standard Name | Long Wavelength | Long Reach |
| Working wavelength | 1310 nm | 1310 nm |
| Typical distance | 10 km (SMF) | 10 km (SMF) |
| Fiber optic type | Single mode (commonly used), can also be used for multi-mode | Single mode only |
| Application | Data center, campus network | Metropolitan area network, long-distance transmission |
