You'll find these three common 10G SFP+ module types — SFP-10G-SR, SFP-10G-LRM, and SFP-10G-LR are commonly used in fiber optics. Cisco, Juniper, Arista, FS, and other large manufacturers have this kind of production, mainly used in switches and routers.
SFP refers to a small form-factor module that can be hot-pluggable. 10G stands for their maximum transmission rate of 10.3 Gbps suitable for 10 Gigabit Ethernet. SR, LRM, LR represent the transmission distance of the 10G optical module. The transmission distance they represent is from short to long.
More about 10G SFP+ Modules Cassificaion
The SFP-10G-SR is a 10GBASE-SR SP+ module, which can reach up to 300 meters matched with OM3 Multimode Fiber (MMF), known as the lowest-cost, lowest-power modules implemented with a VCSEL.
The SFP-10G-LR is a 10GBASE-LR SP+ module that adopts Distributed Feedback Laser (DFB). It operates at a nominal wavelength of 1310nm and can reach up to 10 km over Single Mode Fiber (SMF). It is used in wiring buildings on a large campus or even setting up a Metro Area Network (MAN).
The SFP-10G-LRM is a 10GBASE-LRM Module that supports link lengths of 220m on standard Fiber Distributed Data Interface (FDDI) grade multimode fiber. To ensure that specifications are met over FDDI-grade, OM1 and OM2 fibers, the transmitter should be coupled through a mode conditioning patch cord. No mode conditioning patch cord is required for applications over OM3 or OM4.
Let us make a comparison of the similarity and differences, which will help you choose the right 10G SFP+ module depending on your application.
|Rate||10 Gbps||10 Gbps||10 Gbps|
|Interface||LC duplex||LC duplex||LC duplex|
|Laser Type||VCSEL 850nm||DFB 1310nm||FP 1310nm|
|Fiber Optic Type||MMF||SMF||SMF/MMF|
|Transmitted Light Power||-7.3～-1dBm||-8.2～0.5dBm||-6.5~-0.5dBm|
|Received Sensibility||< -11.1dBm||< -14.4dBm||< -8.4dBm|
|Commercial Temperature||0～ 70°C (32 ～ 158°F)||0～ 70°C (32 ～ 158°F)||0～ 70°C (32 ～ 158°F)|
|Application Range||Only used for short distance connections||Only used for long distance connections||Only used for short distance connections|
SFP-10G-SR transceivers and SFP-10G-LRM transceivers both support multimode fiber transmission. The former supports 300m over OM3 cable and 400m over OM4 cable while the latter supports 200m over OM3 or OM4 cable. Normally, when the transmission distance is less than 300 meters, SFP-10G-SR is recommended. However, if you have other requirements, for example, 200m transmission with modal bandwidth of 500 MHz km, then an SFP-10G-LRM transceiver is necessary. For more subtle differences, refer to the following chart:
|Wavelength (nm)||Cable Type||Core Size (Microns)||Modal Bandwidth (MHz km)||Cable Distance|
|SFP-10G-SR/ SFP-10G-SR-X||850||MMF||62.5||160 (FDDI)||26 m|
|62.5||200 (OM1)||33 m|
|50||500 (OM2)||82 m|
|50||2000 (OM3)||300 m|
|50||4700 (OM4)||400 m|
Given that many users are still using OM1 and OM2, the pursuit for SFP-10G-LRM fiber optic transceiver is bigger than SFP-10G-SR optical transceiver because the transmission distance of SFP-10G-SR is only 33m over OM1/OM2, while SFP-10G-LRM can support 220m over OM1/OM2.
For single mode transmission within 300 meters, choosing SFP-10G-LRM is an economical solution. For 2-10km transmission, the SFP-10G-LR is the only option.