Choosing the Right Fiber Patch Cable for 40G Network

Nowadays, the demands for data transmission rate and data capacity become much higher than ever before, which makes 40G Ethernet network more and more prevalent. Under this inevitable trend, 40G Quad Small Form-factor Pluggable (QSFP+) transceiver is designed for 40G migration as the most economic and effective module. Do you have a good knowledge about 40G QSFP+ transceiver? Are you interested in upgrading your system into 40G Ethernet network? If yes, there is an important and basic problem you need to consider and deal with before the migration. Which kind of fiber patch cable is the most suitable and cost-efficient for connecting your 40G QSFP+ transceiver?

As we all know, switches are need to be connected so as to form the whole 40G transmission network. How to connect these switches? As a basic component in the connection, fiber patch cable plays an indispensable role in connecting 40G QSFP+ transceivers which are plugged in Ethernet switches. Then the whole connection can be done, which is shown in the following figure for your reference.

Considering that the quality of the connection will largely affect the reliability and stability of the whole 40G network, the selection for fiber patch cable should be a priority in 40G migration. Since the connectivity of 40G is much more complex than ever, this article will provide the fiber patch cable selection guide as detailed as possible for connecting 40G QSFP+ transceivers.

Choosing the proper fiber patch cable becomes a big issue in 40G network not only because of the switch connections necessity, but also because of the transmission principle of the fiber optic signals and the high density trend of 40G transmission. To ensure the quality of the whole 40G network, two factors should be taken into consideration when selecting fiber patch cable, which are cable type and connector type.

As the performances of optical signals are completely distinct over different fiber optic cables, selecting the most suitable cable type is essential. In principle, all the fiber optic cables can be used in 40G network. But if the data transmission rate increases, the optical signal transmission distance will get shorter. Hence, the longer the signal can be transmitted by fiber optic cable, the higher the performance of fiber optic cable will be.

As a result, OM3 patch cable and OM4 patch cable are suggested for connecting 40G QSFP+ transceivers in short distance, while the single mode fiber patch cable is the best choice for long transmission in 40G network. As for the two upgraded multimode cables, OM3 can support 40G network at lengths up to 100 meters and OM4 can support 40G network longer, up to 150 meters. Meanwhile, if you want to set up a long distance transmission in 40G network, you are suggest to choose single mode fiber patch cable that can transmit signals up to 10km.

The selection of connector type of the fiber patch cable depends on the interface of 40G QSFP+ transceiver. At present, there are two interfaces commonly adopted by 40G QSFP+ transceiver which are MTP interface and LC interface. In short transmission application, 40G QSFP+ transceivers with MPO interface are usually used, thereby the patch cable with MTP connectors should be also selected. In long transmission application, 40G QSFP+ transceiver is always with LC interface, so that patch cable with duplex LC connector should be used.

However, there are several 40G QSFP+ transceivers, for instance, 40GBASE-PLR4 and 40GBASE-PLRL4, which have MPO interfaces to support long transmission distance. If you choose these 40G QSFP+ transceivers for long distance transmission, the patch cables for connection should be also with MPO connectors.

When selecting the right fiber patch cables for 40G QSFP+ transceivers, both cable type and connector type must be considered that are closely related to transmission distance, 40G network flexibility and reliability. Hope the selection guide for fiber patch cable in this paper is helpful for you to design your 40G Ethernet network.