Data transmission speed reaches 200G per second within ten kilometers. New laser may form the basis of next-generation Ethernet technology

Researchers at Japan's Langmeitong Corporation have developed a new distributed feedback (DFB) laser and demonstrated that it can transmit data at 200Gb/s (gigabytes per second) over a record-breaking distance of 10 kilometers. This research helps advance network technology, allowing Internet data centers to process data at unprecedented levels. Langmeitong will present the new research at the Optical Fiber Communications Conference (OFC) in San Diego, California, from March 5 to 9.

Researchers say this research will help develop next-generation data centers for 800G and 1.6T Ethernet. In particular, new technology shows that electroabsorption modulators with integrated distributed feedback (EA-DFB) lasers can even use conventional PAM4 (pulse amplitude modulation) technology for transmission up to 10 kilometers.

Schematic diagram of LE type EA-DFB laser. Image source: Japan Langmeitong Company

As communication traffic continues to increase, there is increasing focus on implementing next-generation Ethernet technologies, such as 800G and 1.6T Ethernet, to help data centers meet growing demands. Although the same PAM4 technology used for 2km transmission in today's 400G Ethernet is being considered for 800G, new technology is needed to enable long-distance data transmission for interconnections between data center areas.

In this new work, the researchers developed EA-DFB lasers to achieve longer transmission distances. They first used the new laser to demonstrate 5-km transmission of 225Gb/s PAM4 using the coarse wavelength division multiplexing (CWDM) band at 50°C. They also used lasers to complete 10-kilometer transmission of 225Gb/s PAM4 at the 1293.5nm band. The dispersion of this wavelength is smaller than the range of wavelengths allocated to CWDM, which is commonly used to send multiple optical signals simultaneously through optical fibers. Dispersion will cause optical signal degradation, which is not conducive to longer-distance transmission.

In experiments, the performance of the new laser was stable. Researchers say that EA-DFB is a promising light source for the upcoming 800G Ethernet technology applications.

Imagine that you have 200Gb of video resources stored in your mobile hard drive, and you want to transmit them all to a friend 10 kilometers away from you through the network. Using this new laser technology, the transmission is completed in just 1 second. In the blink of an eye, your friend has received everything. If network transmission becomes so fast in the future, will human society undergo earth-shaking changes? Of course, when paying attention to the powerful performance of this new laser, we should not ignore the key core technology behind it - the research and development of new generation optoelectronic components and related new materials.