40GBASE-SR4 vs 40GBASE-LR4: Which Option is Best for You?



When it comes to fiber optic transceivers, there are a few different options to choose from. In this blog post, we will compare 40GBASE SR4 vs 40GBASE LR4 and help you decide which option is best for your business. Both of these options offer great performance and value, but they each have their own unique benefits that may be better suited for your specific needs. Let’s take a closer look at both of these options!

40GBASE-SR4 Wiki

40GBASE-SR4 is a 40 Gb/s Ethernet standard. 40GBASE-SR4 QSFP+ modules offer a high port density and low power consumption option for data centers looking to upgrade their network infrastructure to support 40 Gb/s speeds. It supports a data rate of 40 Gigabits per second over 150 meters of optical fiber using OM4 multimode fiber. The standard defines two types of modules: the QSFP 40G SR4 module and the QSFP 40G LR4 module. The SR4 module is intended for short-range applications with a reach of up to 150m while the LR4 module is intended for long-range applications with a reach of up to 10 km. 40GBASE-SR4 uses a wavelength of 850 nm and requires 4 lanes of 10 Gb/s each. MTP/MPO connectors are used for direct connection to an optical fiber cable or via an intermediate connecting device.OM3 or OM4 fiber cables are recommended for use with 40GBASE-SR4.

40GBASE-LR4 Wiki

40GBASE-LR4 is a 40 Gigabit Ethernet standard, providing 40 Gbps data rates over single-mode fiber optic cables with a maximum link length of 10 kilometers. The 40G QSFP+ LR4 optical module adopts the hot-pluggable QSFP+ package, and the operating wavelengths are 1271, 1291, 1311 and 1331nm. It is a 4-channel full duplex transceiver module. At the transmitting end, four 10Gbps serial data streams are sent to the driving core, which controls the direct modulation laser, and then the optical signals output by the four lasers are loaded into one single-mode fiber through one optical multiplexer and one LC connector. At the receiving end, four 10Gbps optical signals flow through the optical demultiplexer to four channels, and the optical signals of each channel flow through the PIN photodetector and the radiation limiter for output.

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The 40GBASE-SR4 optical module adopts MPO connector, and the working wavelength is multimode 850nm. When it is used with OM3 multimode fiber, the transmission distance is 100m and when OM4 multimode fiber is used, the transmission distance is 150m. It is mainly used to realize a short-distance connection between network devices in the data center. The 40GBASE-SR4 optical module can not only use an MPO fiber jumper to realize the connection between two 40G network devices but also can be used with an MPO-LC fiber jumper to realize the connection between 40G network equipment and 10G network equipment.

The 40GBASE-LR4 optical module adopts duplex LC connectors, the working wavelengths are 1271nm, 1291nm, 1311nm, and 1331nm, and the transmission distance with single-mode fiber can reach up to 10km. It is mainly used to realize medium and long-distance connections between data center network equipment.