Introducing OPTCORE Single Lambda 100G QSFP28 Transceiver: A Comprehensive Guide

We all know that there are many types of 100G optical modules, including the most well-known 100G-SR4, 100G-CWDM4 using CWDM technology, and 100G-LR4 suitable for long-distance transmission. However, in this article, we will introduce a type of module that improves transmission efficiency through a special technology: Single Lambda QSFP QSFP28 Optics. As the demand for bandwidth in high-density networks continues to grow, traditional 100G optical modules are gradually no longer suitable for all scenarios. This technology, which uses single-wavelength high-speed transmission, redefines an optical layer architecture. This technology also provides a more efficient path for the evolution to 400G networks.

What is Single Lambda 100G QSFP28 Transceiver?

How it works

Single Lambda QSFP 100G Optics uses the 100G single lambda optical specification. This specification is defined by the 100G Lambda MSA, and like other high-speed transmission technologies, it is based on PAM4 signaling. However, this technology allows 100G transmission, which originally required multiple channels or multiple wavelengths, to be completed on a single wavelength. This implementation provides a more cost-effective and efficient solution for multi-layer switching and high-density transmission. The structure where each wavelength supports 100G transmission greatly simplifies the optical architecture of the module. This reduces component complexity and lowers cost.

This implementation relies on the cooperation between PAM4 modulation and DSP (digital signal processing). It also receives four 25G NRZ electrical signals from the host side. In Single Lambda QSFP 100G Optics, these signals do not directly drive optical devices. The electrical signals enter the DSP for re-encoding, where four NRZ signals are mapped into a single PAM4 signal, allowing each symbol to carry 2 bits of information (00, 01, 10, 11). At the same time, the DSP applies pre-emphasis and equalization to compensate for high-frequency loss and signal distortion during high-speed transmission. The processed PAM4 electrical signal drives a single laser to transmit an optical signal on one wavelength. During the whole process, the optical transmission path always stays as a single-channel structure.

At the receiver side, the optical signal is converted back into an electrical signal through a photodetector and then enters the DSP again for processing. This complete processing chain is the key to the stable operation of 100G single lambda. Compared to stacking optical components, this approach focuses more on improvements in digital signal processing technology.

Types of Single Lambda 100G QSFP28 Transceiver

Single Lambda QSFP 100G Optics mainly includes three standards. These three standards all rely on 100G single lambda technology. When selecting, the main difference is the link design, which determines the maximum transmission distance. This also means differences in application scenarios and budget.

• 100GBASE-DR: 500m / inside data center
• 100GBASE-FR: 2km / medium-distance interconnect
• 100GBASE-LR: 10km / metro or campus connection

Single Lambda 100G QSFP28 vs Traditional QSFP28 / vs 400G Modules

Traditional 100G QSFP28 modules, such as SR4, LR4, CWDM4, and PSM4, all require four channels for parallel transmission. In this transmission method, each channel corresponds to one laser and one receiver. The more optical components used, the more complex the structure becomes. It is well known that most of the cost of an optical module comes from its optical components. The 100G single lambda technology allows a module to use only one laser and one receiver. Therefore, the design of Single Lambda QSFP 100G Optics greatly reduces cost (about 40%) without affecting transmission efficiency. In addition, since it does not require WDM or parallel fibers, single-wavelength transmission also simplifies cabling and maintenance.

Advantages of 100G Single Lambda

After understanding the principle, we can look at what benefits Single Lambda QSFP 100G Optics brings to your network.

• Low cost and higher cost-performance: By reducing the number of lasers and receivers, it saves a large amount of optical component cost compared to SR4, while keeping the 100G transmission rate unchanged.
• Longer transmission distance: The 100G QSFP28 DR module (also called DR1) supports up to 500m, the 100G QSFP28 FR (or FR1) module supports up to 2km, and the 100G QSFP28 LR supports up to 10km. ER1 may support longer distances. Multiple options support more distances and more scenarios.
• High reliability: The internal DSP structure and FEC technology ensure stable link transmission and low bit error rate even with single-wavelength transmission. Reducing optical components does not reduce transmission quality.
• More flexible upgrade path: Single Lambda reduces internal components, which lowers thermal pressure and makes it easier to increase port density. For 400G upgrade scenarios, Single Lambda can directly act as the 4×100G building block.

100G Single Lambda Driving 400G Development

In existing IEEE standards, early 400G implementations usually use 8×50G PAM4 channels, such as 400G SR8. This architecture improves data transmission per channel, but as bandwidth increases, it brings higher complexity in optical interfaces and module packaging. It also leads to higher power consumption and thermal challenges, which are not ideal for long-term development. 100G Single Lambda provides a foundation with a higher per-channel data rate. The higher rate per wavelength allows 400G links to move from “8×50G” to “4×100G”. This reduces the number of optical channels and lowers the size of the optical engine and internal loss.

In real deployment, it also plays an important role in controlling the overall thermal distribution. In high-density environments, it makes more designs possible. Single Lambda is not only for 100G links, but also redefines 400G implementation at the “channel level”, achieving a better balance between cost, power, and density.

Upgrading from 100G QSFP28 to 400G QSFP-DD

The upgrade from 100G QSFP28 to 400G QSFP-DD faces challenges in interface structure, link breakout methods, and device compatibility. The 100G system based on Single Lambda provides a more direct mapping. Each 100G link itself is an independent “100G channel unit”, allowing a 400G QSFP-DD port to combine or split into 4×100G without complex channel reconfiguration or rate conversion logic. This technology changes the upgrade from a full link redesign into a channel-level combination, greatly improving deployment efficiency.

FAQ

Is a single lambda single-mode?
No. Single-mode refers to the type of fiber used, while single lambda refers to a technology type. They are not directly related. In practice, Single Lambda modules usually use single-mode fiber because it is more suitable for medium and long distances.

Conclusion

Single Lambda 100G QSFP28 Transceiver is one of the most cost-effective and high-quality solutions for high-speed transmission today. It is also an important bridge for a smooth upgrade to 400G networks. A full understanding of this technology helps you better choose the right modules when building new links. Different 100G solutions depend on your application scenarios and budget. Learning more and choosing reliable, compatible brands can reduce trial-and-error costs.

Read more

• 100GBASE-SR4 vs. 100GBASE-BiDi SR vs. 100GBASE-SR10: What is the difference?
• 100G Transceiver, DAC, or AOC: Which one to Choose?
• What Is 100 Gigabit Ethernet? A Beginner’s Guide