QSFP28 supports speeds of up to 100 Gigabits per second (Gbps) per port.

How to Choose the Right 100G QSFP28 Optical Transceivers?

Ways to Select 100G QSFP28 Transceivers

The first thing to make sure of before purchasing is the transmission distance you expect the transceivers to reach. Here are a few tips to choose the right QSFP28 transceivers for your 100G deployment based on different transmission distances.

1. Copper DAC Used Inside Racks: 1-5m

QSFP28 DACs are a very cost-effective I/O solution for 100GbE connectivity within 5m. If your 100G deployment is within 5m intra racks, the DACs would be good for you.

2. Multimode Fiber Use Between Switches: 5-100m

For 100G cabling between switches, there are two options to choose from. One is to use QSFP28 AOC for a distance of 3-20 meters. And the other option is to use a QSFP28 SR4 transceiver with 12-fiber MTP OM3/OM4 cable to reach a distance of up to 100m.

3. Single-Mode Fiber Use Between Switches: 100m-2km

For a distance of 100m-2km, there are two recommendations, QSFP28 PSM4 and CWDM4 transceivers. QSFP28 PSM4 can support up to 500m over 12-fiber MTP single-mode fiber cable. QSFP28 CWDM4 transceivers are suitable for 2km over duplex LC single-mode fiber cable.

4. Single-Mode Fiber for Long Span: ≤10km

For long-distance 100GbE deployment, such as connectivity between two buildings, mostly up to 10 km, QSFP28 LR4 with duplex LC single-mode fiber cable is the preferred option defined by IEEE. Some QSFP28 LR4 modules can even reach a maximum distance of 20km.

5. Transmission Distance Exceeds 10 km

The QSFP28 ER4 optical transceiver provides superior performance for 100G Ethernet applications up to 40 km links. It converts 4 input channels of 25Gb/s electrical data to 4 channels of LAN WDM optical signals and then multiplexes them into a single channel for 100Gb/s optical transmission. There are also QSFP28 ZR4 100G module and DWDM PAM4 module for extended long-haul transmission up to 80km.