The rapid growing bandwidth keeps driving the need for 100G transceivers to build data centers, enterprise, long-haul networks. Just as 1G, 10G optical modules, 100G QSFP28 transceivers also have single-mode and multimode categories to support short and long distance network links. So what kind of 100G QSFP28 transceivers are included? What distance can each 100G QSFP28 support?
Multimode 100G QSFP28 modules are used for short distance applications, such as QSFP28 Cisco QSFP-100G-SR4-S 100GBASE-SR4 transceiver. It provides 100GBASE-SR throughput at a wavelength of 850 nm by connecting with multimode MTP/MPO cable. It can support the link lengths up to 70 m over OM3 MPO fiber patch cable and 100 m over OM4 MPO fiber jumpers.
But there is a special 100G QSFP28 transceiver–QSFP-100G-PSM4-S. This QSFP28 is a single-mode transceiver. It carries 100G data over 12-fiber single-mode MPO fiber patch cords. However, the maximum link lengths it can support is only 500 meters.
To support long distance signal transmission, single-mode transceivers are generally selected. The following will list some 100G QSFP28 modules which can reach the link distance from 1 km to 10 km.
QSFP28 100GBASE-CWDM4. This transceiver applies WDM multiplexing and demultiplexing technique and carries 100G Gigabit Ethernet signal over four wavelengths. Different from the above two 100G QSFP28 optics, it’s configured with duplex LC interfaces. With QSFP28 100GBASE-CWDM4 modules, you can build networks with link lengths up to 2 km over single-mode duplex LC patch cords.
QSFP28 100GBASE-LR4. This hot-pluggable 100G QSFP28 form factor can support 103.1Gbps data rate. It’s compliant with the QSFP28 MSA and IEEE802.3ba 100GBASE-LR4. The 100G data is transmitted over four wavelengths. Because of multiplexing and demultiplexing within this QSFP28 transceiver, it matches duplex LC patch cords. And it can support links up to 10 km over single-mode LC fiber cable.
In fact, 10km link lengths of 100G can’t meet users’ demands. So 100G QSFP28 which can support over 10km lengths are needed to build long-haul network. Due to the optic package size and the maximum power, the distance supported by 100G QSFP28 transceivers are restricted. Vendors are required to research and develop optics that allow for existing high power components and devices to consume lower power in a smaller space. It’s said there are 100G QSFP28 ER4 and 100G QSFP28 ZR4 transceivers in the market. Each can support the maximum network link lengths up to 30 km and 80 km. But consumers can’t easily get those 100G QSFP28 modules. But we believe that ER4 and ZR4 technology will be available in the market sooner or later.
At present, if your switch ports are QSFP28 and you need to build 100G network links over 10km, you are suggested to apply amplification technology. The other method is 100G CFP ER4 that support 40km link lengths. Of course your switch port should be CFP or you can find a device to convert QSFP28 to CFP.
Now people can get 100G QSFP28 transceivers for link lengths up to 10 km. Yet not too many transceiver vendors have enough stocks. In the Internet era, what is important is the speed. Thus, seek for reliable vendors who have huge stocks of 100G QSFP28 like FS.COM. And we will release 100G QSFP28 ER4 and 100G QSFP28 ZR4 in the future to support longer distances.