FIBERSTAMP 400G QSFP-DD 2×FR4 optical transceiver module is designed for medium-distance interconnect in data centers, compliant with the IEEE 802. The key laser technologies used in 100G/200G/400G/800G transceivers are EML and DML. So what are the differences between them? This article will discuss the basics of EML and DML and highlight their key differences. EML vs DML: What Are They? DML refers to a directly modulated laser. 3-2018 400GBASE-DR4 and 400GAUI-8 standards. The 425 Gigabit signal is carried over four parallel lanes by one wavelength per lane. the PAM4 pattern signalhas twice the transmission rate of the NRZ code, can carry more. Comparison of advantages and disadvantages between different optical chips in 400G series optical modules: In terms of bandwidth, the current research on EML bandwidth has shown that it can reach 60GHz, while Silicon Photonics MZM can reach 50GHz. With a transmission rate of 400G, the 400G.