Getting to Know About QSFP-40G-UNIV Transceiver

As the switching applications requiring higher bandwidth increased, the need to upgrade from 10G to dense 40 Gigabit Ethernet switching connection also goes on rise. But the optical transceivers widely used at present require to redesign the data center layout if migrating to 40G, for the existing fiber infrastructure cannot satisfy this migration requirement. However, the QSFP-40G-UNIV transceiver can solve this problem perfectly. Why QSFP-40G-UNIV transceiver can resolve the problem successfully? Let’s first to know the basics about it.

Basics of QSFP-40G-UNIV Transceiver

The “UNIV” in item “QSFP-40G-UNIV” means “Universal”. As we all know, common optical transceiver only can operate either on single-mode fiber (SMF) or multimode fiber (MMF), but it can work on both types of fibers. Therefore, QSFP-40G-UNIV transceiver is also called SMF&MMF 40G transceiver or QSFP 40G universal transceiver. This transceiver is a pluggable optical transceiver in an industry standard QSFP+ form factor. It has four channels of 10G multiplexed inside the module to transmit and receive an aggregate 40G signal over a single pair of single-mode or multimode fiber. And it uses a duplex LC connector that makes it work with a wide range of fiber optic cables, including multi-mode OM3 and OM4 and single mode (OS1). Besides, QSFP-40G-UNIV transceiver supports distances up to 150 m over OM3 or OM4 multimode fiber and up to 500 m over single-mode fiber (different vendor may have different specifications).


Differences and Advantages of QSFP-40G-UNIV Transceiver

There are various types of short reach QSFP transceivers such as QSFP-40G-SR4 and QSFP-40G-XSR4. The longest reach of them on OM3 is 300m. And most of them use MPO-12 connectors and ribbon fiber infrastructure. As a result, if users have to deploy new fiber to upgrade from 10G to 40G or to install MTP/MPO fiber systems, they have to invest more money to change the existing network systems. However, QSFP-40G-UNIV transceiver is different. It has LC connectors and supports several types of cables, allowing for seamless migrations from existing 10 to 40GbE networking without requiring a redesign or expansion of the fiber network.

Here are the advantages of QSFP-40G-UNIV transceiver.

  • Uses existing duplex fiber infrastructure for 40G
  • Identical transceiver for both multi-mode and single-mode fiber for simplified operations and investment protection
  • Support for Digital Optical Monitoring (DOM) and passive network Taps for link quality monitoring and passive data analysis
  • Optically interoperable with IEEE 40GBASE-LR4 and 40G-LRL4 for easy connection to routers and switches in existing networks
  • Supported QSFP+ ports on switches without restrictions
Applications of QSFP-40G-UNIV Transceiver

As have mentioned above, QSFP-40G-UNIV transceiver is a kind of optical transceiver that can be used for both single-mode and multimode fibers. With this unique design, it offers a cost-effective connectivity for data centers’ migration. Here is a simple illustration of the applications using QSFP-40G-UNIV transceivers.

Multimode Direct Connections for Cisco Switches

The following figure shows the simplest and cost-effective way to connect two Cisco Nexus 9396PX switches with Cisco compatible QSFP-40G-UNIV transceivers for multi-mode fiber infrastructure. In this connection, except for the required transceivers, an LC to LC duplex multimode fiber patch cable is also needed to link the two QSFP-40G-UNIV transceivers directly.


Single-mode 40GbE Interconnection Solution Using QSFP-40G-UNIV Transceivers

With the special characteristic, the use of Cisco compatible QSFP-40G-UNIV transceiver can help network administrators take greatly advantage of reducing deployment and support. The following figure shows a low cost single-mode 40GbE Interconnection solution. These qsfp+ transceivers are connected with LC duplex SMF fiber patch cables. And two fiber enclosures loaded with MTP LGX cassettes and MTP/MPO trunk cables are also needed to realize this connection.



Without having to redesign or change the existing cable infrastructure, qsfp bidi transceivers enable data centers to run at 10G today and to seamlessly upgrade to 40G. It offers a transition path between single-mode and multimode optics with lower cost and more conveniences. FS.COM supplies 40G QSFP transceivers compatible with other major brands including Cisco QSFP-40G-UNIV, Arista QSFP-40G-UNIV, HPE, etc. And those transceivers are 100% tested to provide a satisfying working performance. You can visit FS.COM or contact for more detailed information.

OM3 vs. OM4 Multi-mode Fiber Cables

With each passing year, the demands for higher data rates and greater bandwidth in data centers grow. An increasing number of sophisticated fiber optical products have been introduced into the telecommunication market, including fiber patch cables (single-mode fibers (SMFs) and multi-mode fibers (MMFs)), with MMFs being preferred by users. MMFs have four types, OM1, OM2, OM3 and OM4. This article mainly details the differences between OM3 and OM4, helping you clear off the confusion of these two types.

OM3 and OM4 Compatibility

The first thing to note is that OM4 is completely backwards compatible with existing OM3 systems. The connectors and termination of OM3 and OM4 are same. Besides, both OM3 and OM4 are Laser Optimised Multi-mode Fiber (LOMMF) share the same fiber core size of 50/125. So, what are the differences between them?

OM3 vs. OM4

OM4 differs from OM3 mainly in their attenuation and dispersion provided. Let’s first see the following table which shows the attenuation and dispersion of OM3 and OM4.

Type Maximum Attenuation at 850nm Minimum Fiber Bandwidth at 850nm
OM1 3.5 dB/Km 2700 megahertz*Km
OM2 3.0 dB/Km 4700 megahertz*Km
  • Attenuation Analysis

OM4 cable has lower attenuation than OM3. Attenuation refers to the reduction in power of the light signal as it is transmitted (dB). It’s caused by losses in light through the passive components, such as cables, and connectors, relatively simple to explain. The maximum attenuation at 850nm permitted by OM3 is less than 3.5 dB/Km, while the OM4 is less than 3.0 dB/Km. OM4 causes fewer losses.

  • Dispersion Analysis

Dispersion is the spreading of the signal in time due to the differing paths the light can take down the fiber. Two types of dispersion are available: chromatic and modal. Chromatic is the spreading of the signal in time resulting from the different speeds of light rays, while modal is the spreading of the signal in time resulting from the different propagation modes in the fiber. Here the focus is put on the modal dispersion. The modal dispersion determines the modal bandwidth that the fiber can operate, and this is what the difference between OM3 and OM4 lies in. The minimum fiber bandwidth at 850nm allowed by OM3 is 2700 megahertz*Km, by OM4 is 4700 megahertz*Km, meaning that OM4 can operate at higher bandwidth.

  • Other Considerations Between OM3 and OM4

OM4 is more network reliable than OM3, providing great design flexibility. What’s more, OM4 is able to reach an additional 60% links in the core-to-distribution and in the access-to-distribution channels compared to OM3 in 40G/100G Ethernet applications. In 40G Ethernet transmission using 40G QSFP, OM4 enables 150m length reach. Like Arista QSFP-40G-SR4, this 40G QSFP, when runs over OM4, enables 150m reach with MTP/MPO connector at a data rate of 40 Gbps. The image below shows what the Arista QSFP-40G-SR4 transceiver looks like.

Arista QSFP-40G-SR4

Use OM3 or OM4 for Your Network?

On the one hand, since OM3 are compatible with OM4, these two types are interchangeable when the transmission distance limitations are accessible. But on the other, the additional bandwidth and lower attenuation of OM4 make it more ideal for MMF cabling infrastructure. Whether use OM3 or OM4 for your network, it depends on the specific situations, like cost, and distance required.


After detailed discussion, you may have gained a better understanding of the OM3 and OM4 differences and you can quickly choose MMF types to meet your higher bandwidth system requirements. Fiberstore OM3 and OM4 provide solutions that allow more effective and bandwidth-providing network installations. Besides fiber patch cables, Fiberstore also offers copper cables for your networks, such as QSFP-H40G-CU5M. This Cisco QSFP-H40G-CU5M product listed on Fiberstore is 100% compatible with the equivalent Cisco direct attach copper cables. For more information about fiber patch cables and copper cables, you can visit Fiberstore for more information.