Introduction to 100G Fiber Optic Transceivers

According to the statistics from market research company like IHS, 2016 is the year of 100G modules due to the increasing needs for higher Ethernet speed. Presently, the form factors of 100G fiber optic transceiver module include CXP, CFP, CFP2, CPAK, CFP4 and QSFP28. This article will have a basic introduction to all of these 100G transceiver. The following picture shows the parameters of all the 100G form factors.

100G transceivers


The CFP multisource agreement (MSA) was formally launched at OFC/NFOEC 2009 in March. The CFP form factor, as detailed in the MSA, supports both single-mode and multimode fiber and a variety of data rates, protocols, and link lengths. While the electrical connection of a CFP uses 10 x 10G lanes in each direction (RX, TX), the optical connection can support both 10 x 10G and 4 x 25G variants of 100G fiber optic interconnects. Typically, it refers to 100GBASE-SR10 in 100 meter MMF, 100GBASE-LR10 and 100GBASE-LR4 in 10 km SMF reach, and 100GBASE-ER10 and 100GBASE-ER4 in 40 km SMF reach respectively.

As improvements in technology have allowed higher performance and higher density, which drives the development of the CFP2 and CFP4 specifications. While CFP, CFP2 and CFP4 are electrical similar, they specify a form-factor of 1/2 and 1/4 respectively in size of the original specification. Note that CFP, CFP2 and CFP4 modules are not interchangeable, but would be inter-operable at the optical interface with appropriate connectors.


The CXP was created to satisfy the high-density requirements of the data center, targeting parallel interconnections for 12x QDR InfiniBand (120G), 100G, and proprietary links between systems collocated in the same facility. The CXP is 45 mm in length and 27 mm in width, making it slightly larger than an XFP. It includes 12 transmit and 12 receive channels in its compact package. This is achieved via a connector configuration similar to that of the CFP. Typical applications of CXP in the data center include 100G over Copper (CXP): 7m (23ft) and 100G over multimode fiber: CXP for short reach applications (CFP is used for longer reach applications).


CPAK is another form factor to support 100G fiber optic network. This is a proprietary form factor from Cisco but the interfaces demonstrated are IEEE standards and will interoperate with the same interfaces supported by other form-factors. Cisco CPAK modules combine the greatest density and bandwidth with the lowest power consumption available in the market. They are interoperable with any IEEE-compliant 100GBASE-LR4 or 100GBASE-SR10 for investment protection and product choice.


QSFP28 transceiver is designed for 100G speeds and using the 4×25 wiring specification. Similar to 40G QSFP+ that is implemented using four 10G lanes, the QSFP28 uses four 25G lanes with parallel technology, eliminating the costly gearbox found in the other version of 100G fiber optic transceivers like CFP, CFP2, and the CPAK. Additionally, the QSFP28 transceiver has an upgraded electrical interface to support signaling up to 28G signals, yet keeps all of the physical dimensions of its predecessor. Now, technology of QSFP28 is relatively matured. With the movement to reduce costs, the QSFP28 transceivers become increasing popular in the market.

FS.COM Solution for 100G Fiber Optic Transceivers

Fiberstore (FS.COM) provides 100G CFP, CFP2, CFP4 and QSFP28 transceivers. With serious cost control, the prices of these 100G fiber optic transceivers are much more affordable than the similar products in the market. The following table lists the generic ones. Beside the generic, we also have various 100G fiber optic transceivers compatible for many brands, such as Cisco, Juniper etc.

Part Number Product Picture Description
100G SR4 QSFP28


QSFP28 100GBASE-SR4 850nm 100m Transceiver
100G LR4 QSFP28


QSFP28 100GBASE-LR4 1310nm 10km Transceiver


CFP 100GBASE-LR4 and OTN 1310nm 10km Transceiver


CFP2 100GBASE-LR4 and OTN 1310nm 10km Transceiver


CFP4 100GBASE-LR4 and OTN 1310nm 10km Transceiver