100G DWDM Solution: PAM4 or Coherent?
With the increasing demand for high-speed network applications such as 5G, cloud computing, and storage networks, optical transmission networks are also evolving rapidly. And 100G DWDM solutions have gradually improved and matured. Direct modulation and coherent technology can easily extend the transmission distance up to 80km or even 1000km for metro and DWDM networks. So, what is the difference between these two technologies? Which one is more suitable for 100G DWDM transmission? I believe you will find the answer after reading this article.
What's the 100G DWDM Solution?
100G DWDM solution provides the most straightforward method to connect 100G traffic over long-haul applications. And PAM4 and coherent technologies offer cost-optimized solutions in WDM and ultra-long distances transmission over 80km. So what's the difference between these two technologies? Which one is better for the 100G DWDM solution? Find the answers in the following descriptions.
100G DWDM Solution: What Are 100G PAM4 and Coherent Technology?
QSFP28 PAM4 is a technology encoding two bits of data with four distinct signal levels, and it doubles the signal bandwidth of a connection with each signal level representing 2 bits of logic information. It plays a key role in multi-order modulation and makes PAM4 the most efficient and cost-effective enabler of 100G DWDM solutions. 100G PAM4 QSFP28 transceivers adopt PAM4 modulation technology to achieve high-speed signal transmission and the construction of 100G in large data centers, campuses, and enterprise networks.
100G coherent optics are ideal for metro carriers and regional/long-haul transmission applications (80km-1000km). The figure below shows the application of FS 100G CFP2-DCO transceivers for 200G DWDM network, with a fiber link loss of 25dB, achieving the interconnection of lineside backbone DWDM data centers between 100km.
After reading this article, do you have a better understanding of the 100G DWDM solution? 100G PAM4 is more economical and convenient, but the transmission distance is shorter. The coherent module supports long transmission distance but has limitations on the equipment. The specific choice needs to refer to your actual application requirements.