The singlemode QSFP+ and multimode QSFP+ here mean the QSFP+ transceivers which work at different types of optical fibers, ie singlemode QSFP+ will work with singlemode fiber, while multimode QSFP+ will work with multimode fiber. So, what’s the different between them? And what should we notice when using them? Which one should I choose? In this article, we will have a discussion around this topic.
- Singlemode QSFP+
Singlemode fiber (SMF) has much tighter tolerances for optics used. The core is smaller and the laser wavelength is narrower. This means that SMF has the capability for higher bandwidth and much longer distances in transmission. Singlemode QSFP+ (SMF QSFP+) works mainly in 1310nm wavelength and is mostly used in long distances transmission. There are many different types of Singlemode QSFP+, and different type can achieve different transmission distance, such as 500m, 1km, 2km, 10km and 40km. he color of compatible fiber optic patch cord is yellow. SMF QSFP+ usually uses duplex LC connector, but there also are some types use MPO/MTP connector.
- Multimode QSFP+
Multimode fiber (MMF) uses a much bigger core and usually uses a longer wavelength of light. Because of this, the optics used in MMF have a higher capability to gather light from the laser. In practical terms, this means the optics are cheaper. The common multimode QSFP+ (MMF QSFP+) works in 850nm wavelength and is only used for short distance transmission reaching 100m and 500m. Though it’s not able to transport for long distance, it can transport many kind of optical signals. MMF fiber QSFP+ usually uses MPO/MTP connector, but some SMF&MMF QSFP+ can also use duplex LC connector.
SMF QSFP+ and MMF QSFP+ may have different transmission distance and connectors, which is the most important factors you should consider when to make a decision. In the table below, I display the specifications of some main SMF QSFP+ and MMF QSFP+. Hope to help you to choose the right QSFP+ for your network.
|Type||Wavelength||Fiber and Distance||Connector||Original model|
|40GBASE-SR4 QSFP+||4x850nm||100m(OM3) 150m(OM4)||Male MPO||Cisco QSFP-40G-SR4|
|40GBASE-CSR4 QSFP+||4x850nm||300m(OM3) 400m(OM4)||Male MPO||Cisco QSFP-40G-CSR4|
|40GBASE-LX4 QSFP+||1270,1290,1310,1330 nm||100m(OM3) 150m(OM4) 2km(SMF)||Duplex LC||Juniper JNP-QSFP-40G-LX4|
|40GBASE Universal QSFP+||1270,1290,1310,1330 nm||150m(OM3) 150m(OM4) 500m(SMF)||Duplex LC||Arista QSFP-40G-UNIV|
|40GBASE-PLRL4 QSFP+||4x1310nm||1km(SMF)||Male MPO||Arista QSFP-40G-PLRL4|
|4x10GBASE-LR QSFP+ Lite||4x1310nm||2km(SMF)||Male MPO||Finisar FTL4P1QL1C|
|40GBASE-LR4 QSFP+||1270,1290,1310,1330 nm||10km(SMF)||Duplex LC||Cisco QSFP-40G-LR4|
|40GBASE-LR4-Lite QSFP+||1270,1290,1310,1330 nm||2km(SMF)||Duplex LC||Finisar FTL4C1QL1C|
|40GBASE-LRL4 QSFP+||1270,1290,1310,1330 nm||1km(SMF)||Duplex LC||Arista QSFP-40G-LRL4|
|40GBASE-PLR4 QSFP+||4x1310nm||10km(SMF)||Male MPO||Arista QSFP-40G-PLR4|
|40GBASE-ER4 QSFP+||1270,1290,1310,1330 nm||40km(SMF)||Duplex LC||Cisco QSFP-40G-ER4|
What Should We Notice When Using Singlemode QSFP+& Multimode QSFP+
- Ensure that the QSFP+ 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.
- In general, to 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 winding fiber optic cables when using them. This will increase the attenuation of light in transit.
- If you don’t use the QSFP+, you must use the dust plug to protect the optical bore.
When we choosing the QSFP+ module, we must confirm the transmission distance and wavelength we want to use in. This will help us to choose the right QSFP+ modules more efficiently. In addition, the costs for transceiver modules which keep adding up over time will be a budget pressure for many users. To save more, we can choose the compatible module without sacrificing any quality or reliability but only with a low cost. Fiberstore, an excellent supplier, supplies 100% compatible fiber optic transceiver modules of many brands, such as Cisco, HP, Juniper, Brocade, Finisar etc. with a incredible discount that may be a good choice for you.