With bandwidth demands keep growing, network service providers are looking at 40G or 100G to accommodate the constant traffic surge. For 40G QSFP+ transceivers, they are interfaced with MTP/MPO or LC connectors, which has been introduced in a previous post: 40G Transceivers With MTP/MPO Interface vs. 40G Transceivers With LC Interface. So this article will introduce 100G transceivers (CFP/CFP2/CFP4/QSFP28) which have different interface types.
The 100G optical transceiver market is fragmented by many different implementations. Besides the IEEE standards, there are also 100G transceivers defined by MSA. The following table lists part of the 100G standards.
From the table above, we can see that there are three different interface types for 100G transceivers—24-fiber MPO, 12-fiber MPO and LC duplex. The 100G transceiver with 24-fiber MPO interface uses 20 fibers to transmit data, with 10 lanes at 10 Gbps per lane (10 transmit and 10 receive). The 100G transceivers with 12-fiber MPO interface use 8 fibers to transmit, with 4 lanes at 25 Gbps per lane (4 transmit and 4 receive). This interface standard has been introduced alongside the 100G QSFP28 transceivers to make 40G to 100G upgrade as seamless as possible. And the 100G transceivers with LC interface work over single-mode fiber cables for long-distance transmission.
After knowing about the 100G transceivers standards, let’s move to the 100G transceivers types. There are 100G CFP/CFP2/CFP4 and QSFP28 transceivers. CFP was designed after SFP, but is significantly larger to support 100 Gbps. The electrical connection of a CFP uses 10 x 10Gbps lanes in each direction (RX, TX). The optical connection can support both 10 x 10Gbps and 4 x 25Gbps variants. With improvement in higher performance and higher density, CFP2 and CFP4 appeared. While electrical similar, they specify a form factor of 1/2 and 1/4 respectively in size of CFP. CFP, CFP2 and CFP4 modules are not interchangeable, but would be inter-operable at the optical interface with appropriate connectors.
| Transceiver Type | Interface | Description |
| CFP-SR10-100G | MTP/MPO-24 | CFP 100GBASE-SR10 850nm 150m Transceiver |
| CFP 100g LR4 | LC duplex | CFP 100GBASE-LR4 and OTN 1310nm 10km Transceiver |
| CFP-ER4-100G | LC duplex | CFP 100GBASE-ER4 1310nm 40km Transceiver |
| CFP2-LR4-100G | LC duplex | CFP2 100GBASE-LR4 and OTN 1310nm 10km Transceiver |
| CFP4-LR4-100G | LC duplex | CFP4 100GBASE-LR4 and OTN 1310nm 10km Transceiver |
The 100G QSFP28 transceivers offer 4 independent transmit and receive channels, each capable of 25Gbps operation for an aggregate data rate of 100 Gbps. Among the various 100G transceivers, most of switch vendors choose the QSFP28 transceivers, because they make deploying 100G networks as easy as 10G networks, increasing density, decreasing power consumption and decreasing your price per bit. It’s also notable that the QSFP28 has the same physical size as the QSFP+ commonly used for 40G traffic. This means that switch vendors can increase the traffic throughput by a factor 2.5 without the need to redesign the front panel of their switches.
| Transceiver Type | Interface | Description |
| QSFP28-SR4-100G | MTP/MPO-12 | QSFP28 100GBASE-SR4 850nm 100m Transceiver |
| QSFP28-PIR4-100G | MTP/MPO-12 | QSFP28 100GBASE-PSM4 1310nm 500m Transceiver |
| QSFP28-IR4-100G | LC duplex | QSFP28 100GBASE-CWDM4 1310nm 2km Transceiver |
| 100G QSFP28 LR4 | LC duplex | QSFP28 100GBASE-LR4 1310nm 10km Transceiver |
100G transceivers are boosting greatly for ever. Buying 100G transceivers is imminent. Choose a reliable supplier and buy the quality 100G transceivers right now. FS.COM has completed the inventory for 100G transceivers and you can enjoy the same-day shipping. We highly recommend the 100GBASE-PSM4 QSFP28 transceiver and 100GBASE-CWDM4 QSFP28 transceiver, which are affordable and can meet most of your network demands. For more details about our 100G transceivers, please visit www.fs.com.
Related Article: Four Types of 100G QSFP28 Transceivers Overview
Related Article: CFP Transceiver Module Overview: CFP, CFP2, CFP4 & CFP8