Tag Archives: SWDM

What Is SWDM4 and 100G SWDM4 Transceiver?


With the promotion of OM5 multimode fiber (MMF) and the large-scale deployment of 40G or 100G data center transmission network, SWDM technology has gradually entered people’s field of vision and has begun to be applied. Then, what is SWDM4? What is 100G SWDM4 transceiver? What are the advantages of them? Look at the text below to get all the answers.

What Is SWDM4?

To begin with, you should know what the SWDM is before knowing anything about SWDM4, right? Then, what is SWDM?

Actually, SWDM, whose whole full name is short wavelength division multiplex, is a new multi-vendor technology that promises to provide the lowest total cost solution for enterprise data centers upgrading to 40G and 100G Ethernet with the existing 10G duplex OM3/OM4 MMF infrastructure. What’s more, it can cost-effectively increase bandwidth density for new data center builds and extend the reach when used with OM5 wideband multimode fiber (WBMMF) as well. By the way, OM5 fiber also future-proofs the infrastructure for possible future 200G, 400G and 800G interfaces.

To upgrade data centers to 40G/100G Ethernet without changing the existing duplex MMF infrastructure being used for 10G Ethernet, pluggable optical transceivers with SWDM technology matters a lot. This approach consists of multiple vertical-cavity surface-emitting lasers (VCSELs) operating at different wavelengths in the 850nm window (where MMF is optimized). The four-wavelength implementation of SWDM is called SWDM4, and these four wavelengths (850, 880, 910 and 940 nm) are multiplexed/demultiplexed inside a transceiver module into a pair of MMFs (one fiber in each direction, i.e., a standard duplex interface). Each of the four wavelengths operates at either 10G or 25G, enabling the transmission of 40G (4 x 10G) or 100G (4 x 25G) Ethernet over existing duplex MMF, using standard LC connectors.

Four SWDM4 wavelengths defined by SWDM MSA

What is 100G SWDM4 Transceiver?

SWDM4 transceivers can deliver 40G and 100G connections in the same way a standard SFP+ transceiver connects, using duplex LC OM3 or OM4 cabling. Here, we will focus on the 100G connections. You may know something about 100G transceiver, then, what about 100G SWDM4 transceiver?

Actually, from the name, it is easy to tell that a 100G SWDM4 transceiver is a 100G transceiver featuring SWDM4 technology. It provides 100Gbps bandwidth over a standard duplex MMF, eliminating the need for expensive parallel MMF infrastructure. And it offers a seamless migration path from duplex 10G to 100G.

According to 100G SWDM4 MSA Technical Specifications, a 100G SWDM4 QSFP28 transceiver can be used for links up to 75m of OM3 fiber or up to 100m of OM4 fiber. The Tx port transmits 100G data over 4 x 25Gbps wavelengths, and the Rx port receives data over 4 x 25Gbps wavelengths. The wavelengths are in the “short wavelength” range (from 850nm to 940nm). Of course, you can use the advanced OM5 fiber operating only over two fibers to get better experience (up to 150m) with a higher price as well.

Block Diagram of a 100G SWDM4 QSFP28 Transceiver

Advantages of  a 100G SWDM4 Transceiver

Here are several benefits from using the SWDM4 in 100G environments with MMF:

  • Cost-Effective: It uses two fibers (duplex) instead of eight (SR4), enabling significant fiber infrastructure capex savings.
  • OM5 Supported: It supports links up to 150m over OM5 MMF with only two fibers.
  • Easy Migration to 100G: It enables seamless migrations from both 10G and 40G to 100G without major changes to the fiber infrastructure. It works on legacy OM3 or OM4 duplex MMF as well. The widely deployed 10G-SR, 40G-BiDi and 40G-Universal optics all operate over a single pair of MMF with regular LC termination. So does the 100G-SWDM4 transceiver. Therefore, users don’t need to change the existing cabling or re-terminate.
  • Familiar Tap Modules: It can be tapped using existing 1 x 2 Tap modules just like 10G-SR and 40G-Universal optics with no change or replacements, avoiding additional cost and complexity.


From all the above, you may have a general understanding of the three concepts: SWDM, SWDM4 and 100G SWDM4 transceiver. Given the advantages concerning above, SWDM technology and 100G SWDM4 transceivers might be dominant trends in the near future. Maybe you can keep an eye on it for future network construction. By the way, FS.COM offers a variety of 100G optical modules for you to choose from, such as PSM4, CWDM4, etc.

Related Articles:

How to Make Full Use of OM5 Fiber in 40G/100G Transmission?

Wideband Multimode Fiber: What to Expect From It?

Wideband Multimode Fiber: What to Expect From It?

Multimode fiber (MMF) holds a major position in local area network (LAN) backbone cabling and data center due to its capability to transmit high data rates at relatively low cost. MMF has evolved now to support multi-gigabit transmission using 850 nm VCSEL (vertical cavity surface emitting laser) sources, and the channel capacity of which is greatly improved with the use of parallel transmission over multiple strands of fiber. Wideband multimode fiber (WBMMF), known as OM5, lately comes into our horizon as an alternative to support the escalating data rate and higher bandwidth. Then what can we expect from using WBMMF? This article may give you some hints.

Existing Problems of Multimode Fiber

OM1 and OM2 MMF are developed with the intention to support Fast Ethernet, which fail to support 10 Gbps and 25 Gbps data transmission rates. Hence they are not suggested for new installations. Laser-optimized OM3 and OM4 MMF now play a dominant role in 10G, 40G and 100G Ethernet cabling. However, the demand for bandwidth accelerates so fast, and the VCSEL-based transceiver technology cannot keep pace. Consequently, it’s getting more costly for fiber cabling systems to support next-generation Ethernet migration.

Wideband Multimode Fiber: Taking New Wavelength to Multimode Fiber

Wideband multimode fiber (WBMMF) is designed to carry multiple short wavelength signals that can be aggregated for high bandwidth applications–—a technology known as wavelength division multiplexing (WDM). Unlike conventional multimode fiber that optimally supports a single wavelength, WBMMF can accommodate multiple wavelengths, enabling these multiple wavelengths to simultaneously travel along a single fiber strand.

wideband multimode fiber

In this way, wideband multimode fiber increases each fiber’s capacity by at least a factor of four, allowing at least a fourfold data-rate increase, or a fourfold reduction in the number of fibers. That means, when transmitting four optical signals, instead of using four separate fibers, WBMMF can send down these signals on one fiber over four separate operating windows. For example, 400GbE could be accomplished with 4Tx and 4Rx fibers (today 400GbE over multimode requires 16Tx and 16Rx fibers).

Highlights of Wideband Multimode Fiber

So, what makes wideband multimode fiber standing out from other multimode fibers? Besides that it increases MMF’s utility and extends MMF’s value to customers, WBMMF also has the following advantages:

    • Wideband multimode fiber can support wavelength division multiplexing (WDM) across the 840-953nm wavelength range, at 30nm intervals.

WBMMF wavelength

  • The fiber geometry of WBMMF stays the same as existing OM4 fibers, therefore it is backward compatible with OM4 multimode fiber at 850 nm, making it feasible to retain legacy application support of OM4.
  • Wideband multimode fiber reduces fiber count by a faction of four, but increases capacity to over 100 Gb/s per fiber, enabling Ethernet 100G-SR, 400G-SR4, 1600G-SR16 and Fiber Channel 128G-SWDM4.
Applications of Wideband Multimode Fiber: Short Wavelength Division Multiplexing (SWDM)

Wideband multimode fiber provides better performance for applications using WDM technology. As the parallel multimode fiber MPO cabling is considerably more costly than the multimode fiber LC-duplex patch cord, WBMMF made it possible to use a single pair of LC fiber instead of MPO trunks in direct point-to-point connection. Which helps to reduce fiber count by transmitting multiple wavelengths in the same multimode fiber, and to keep the overall cabling costs to the minimum.



Wideband multimode fiber is a reliable medium to expand your data center or enhance network capacity. With the capability of managing multiple wavelengths, it effectively reduces the number of fibers and enhances total channel capacity, proven to be a cost-effective solution for increasing network bandwidth, and to keep pace with the escalating data demands.

Related Article: WBMMF – Next Generation Duplex Multimode Fiber in the Data Center