What is a 100G QSFP28 Transceiver

The 100G QSFP28 transceiver is a fiber optic communication module used to increase data transmission rates to 100Gbps, typically employing PAM4 modulation technology. It consists of an optical transmitter, optical receiver, module housing, and chipset. This module typically utilizes multimode or single-mode fiber optic cables as transmission media and converts electrical signals to optical signals through electro-optical modulation technology, enabling high-speed data transmission and communication over optical fibers.

100G QSFP28 Four Lambda Transceivers

In transceivers with four lambdas, data transmission is distributed across 4 separate wavelengths. Each lane has its own transmitter and receiver operating at 25Gbps, aggregating to the total data rate of 100Gbps. The SM wavelengths can be further classified to LAN WDM (1295nm, 1300nm, 1305nm and 1310nm) and CWDM (1270nm, 1290nm, 1310nm and 1330nm), with the latter offering better cost efficiency due to the wider separation of wavelengths.

Figure 1: Singlemode (SM) QSFP28 4 lambda configuration

The QSFP28 modules that can be offered are:

100G QSFP28 Single Lambda Transceivers

In single lambda transceivers, data transmission occurs over a single optical wavelength, using 1 channel/ lane, allowing higher data rate over a pair of optical fiber. Unlike 4 lambda transceivers, single lambda technology simplifies the design of transceivers with reduced optics, thus reduces power consumption and costs. The single lambda transceiver supports only SM transmission, ranging from 500m (DR1), 2km (FR1) and 10km (LR1).

Figure 2: Singlemode (SM) QSFP28 Single lambda configuration

CWDM Single Lambda QSFP28 transceiver module is designed for use in 100Gbps Ethernet links over 10km single mode fiber, incorporating one channel optical signal, on either 1270, 1290, 1310, or 1330nm. Typically, they are used in Data Center Environment for connecting 400Gbps Ethernet CWDM wavelengths, and break-out to specified 100Gbps CWDM wavelengths for leaf-spine networks.

CWDM Single Lambda QSFP28 transceiver:

DWDM Single Lambda QSFP28 transceiver module is designed for use in C-band DWDM networks with 100GHz ITU Grid spacing for Data Center Interconnectivity. The modules have fixed DWDM wavelengths that are plugged directly into transponders, routers, or switches. In most cases it can achieve 2km without DCM (Dispersion Compensation Module) and EDFA (Erbium-Doped Fiber Amplifier). However, for long and extended distances up to 120km, DCM and EDFA are required to compensate fiber link loss and fiber dispersion. Starview can provide you the complete solution for such requirements.

DWDM Single Lambda QSFP28 transceiver:

How to Select the Best QSFP28 Optics?

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.

100G QSFP28 Modules: FAQs

Q: What compatible brands of Walsun QSFP28 modules are available?

A: Walsun offers high-quality 100G QSFP28 transceivers that are compatible with mainstream brands including Cisco, Arista, Juniper, Brocade, Dell, Extreme, HW, H3C, Ciena, Mellanox, IBM, Generic, Walsun, Edge-Core, Palo Alto Networks, Avago, Allied Telesis, Check Point, Chelsio, F5 Networks, etc.

Q: What's the difference between Walsun QSFP-100G-ER4L-S and QSFP-100/112G-ER4 transceiver?

A: QSFP-100G-ER4L-S QSFP28 transceiver module is designed for use in 100GBASE Ethernet throughput up to 40km over single mode LC fiber cable. While the QSFP-100/112G-ER4 QSFP28 is a dual rate optical transceiver, supporting data rate of 103.1Gbps and 112Gbps. It is suitable to be used in various applications, such as 100GBASE Ethernet, telecom, 5G network mid/backhaul.

Q: What's the difference between Walsun QSFP-100G-PSM4-S and QSFP-100G-CWDM4-S?

A: QSFP-100G-CWDM4-S optical transceiver is designed with LC duplex connector, supporting the maximum transmission distance up to 2km. While QSFP-100G-PSM4-S optics is designed with MTP/MPO connector and the maximum transmission distance is 500m. Usually QSFP-100G-CWDM4-S module is more expensive than QSFP-100G-PSM4-S module. 

Q: Will Walsun 100GBASE-ER4 QSFP28 optical transceiver module work on a CWDM or DWDM Mux/Demux?

A: No. CWDM or DWDM Mux/Demux only support CWDM or DWDM transceiver. So our 100G ER4 module cannot be used directly with the 1310 channel port of CWDM Mux/Demux, because of its much greater working bandwidth than that of the channel port. But it is possible to transmit 100G data through the special port (provided that there is one on your device).

Conclusion

Based on above profile for 100G QSFP28 transceiver, do you have any idea to choose the module for what you need? If you have any questions, you are so much  welcomed to contact us directly by E-mail sales@walsun.com or phone.