Which One to Choose, Singlemode QSFP+ or Multimode QSFP+?

Fiber optic transceivers also have singlemode and multimode types according to the fiber they work with. A simglemode QSFP+ transceiver works with singlemode fiber, and a multimode QSFP+ transceiver works with multimode fiber. What are thwy and what is the difference between them? How to choose? A cpmparison between these two kinds of QSFP+ transceivers will be given in this post.

Singlemode QSFP+ vs. Multimode QSFP+

Singlemode QSFP+: Singlemode fiber (SMF) has a tighter tolerance. The core of a singlemode fiber is smaller and the laser wavelength is narrower, which means that SMF has the capability for higher bandwidth and much longer transmission distances. Singlemode QSFP+ (SMF QSFP+) transceiver works mainly in 1310nm wavelength. It is mainly used for long distance transmission. There are several different types of singlemode QSFP+ transceivers. And different types can achieve different transmission distances, such as 500m, 1km, 2km, 10km or even 40km. For example, Cisco QSFP-40G-LR4 compatible 40GBASE-LR4 QSFP+ transceiver, as shown below, is a singlemode QSFP+ transceiver, uses duplex LC connector, and can transmit up to 10km. SMF QSFP+ transceivers usually use duplex LC connectors, and some types can use MPO/MTP connectors.

Multimode QSFP+: Multimode fiber (MMF) has a much bigger core and usually uses a longer wavelength of light. Optics used in MMF have a higher capability to gather light from the laser. In practical terms, this means that the optics can be cheaper. Common multimode QSFP+ (MMF QSFP+) transceiver works in 850nm wavelength and is mainly used for short distance transmission reaching 100m and 500m. For instance, Cisco QSFP-40G-SR4-S compatible 40GBASE-SR4 QSFP+ transceiver, as shown below, is a multimode QSFP+ transceiver, uses MTP/MPO connector, and can transmit up to 150m over OM4 MMF. Multimode QSFP+ transceiver is not able to transmit over long distance, but it can transport many kinds of optical signals. MMF QSFP+ transceivers usually use MPO/MTP connectors, but some SMF&MMF QSFP+ transceivers can also use duplex LC connectors.

Which One to Choose, Singlemode or Multimode?

SMF QSFP+ transceiver and MMF QSFP+ transceiver have different transmission distances and interface connectors, which are the two important factors you should consider when making make a decision. SMF QSFP+ transceivers are for long transmission distances and MMF QSFP+ transceivers are mainly for short transmission distances.

Notes for Using Singlemode QSFP+ and Multimode QSFP+

• Ensure that the QSFP+ transceivers in both ends of the fiber patch cord are of the same wavelength. A simple method is that the color of the modules must be consistent.
• Ensure the data accuracy. Short-wave QSFP+ modules use with multimode fibers (ie. aqua OM3 or OM4 fiber patch cord), while long-wave QSFP+ modules use with single-mode fiber (ie. yellow fiber patch cord).
• Do not over bend or wind fiber optic cables when using them, which will increase the attenuation of light in transmission.
• Use the dust plug to protect the optical bore when the QSFP+ transceiver is not in use.

Conclusion

When choosing a QSFP+ transceiver, first you need to figure out the transmission distance and wavelength you need. It is very crucial and can help you choose the right QSFP+ module. Besides, the cost of transceiver modules is also a very important factor for your consideration. An alternative is you can choose compatible modules without sacrificing quality and reliability. Fiberstore provides all kind of 100% compatible QSFP+ modules branded by many famous companies, such as Cisco, HP, Juniper, Brocade, and Finisar, etc.