New laser lays the groundwork for next-generation ethernet technology

Japanese scientists have developed a new type of distributed feedback laser (DFB) and have shown that it can be used to transmit data at 200 Gb/s over a record distance of 10 km. This research could help advance the networking technology that allows internet data centers to handle unprecedented levels of data.

Kazuki Nishimura, an optical engineer in Lumentum Japan’s Datacom Business Unit, will present new research at Optical Fiber Communications Conference (OFC)taking place from 5 to 9 March 2023 in San Diego, California, USA.

“The research contributes to the development of next-generation data centers for 800G and 1.6T ethernet networks. In particular, the new technology proposes integrated power absorption modulators with distributed feedback lasers ( EA-DFB) can work even for 10 km transmission using conventional PAM4 (pulse amplitude modulation), which is defined as simple intensity modulation (IM/DD) direct detection scheme, “Nishimura said.

As media traffic continues to grow, there is increasing focus on deploying next-generation ethernet technology, such as 800G and 1.6T ethernet, to help data centers meet growing demand. . Although the same PAM4 technology used for 2km transmission in 400G ethernet is being considered for 800G today, a new technology is needed to transmit data over longer distances for connections between central areas. data center or campus.

In the new work, the researchers developed a compound electrode absorption (EA) modulated DFB laser to achieve longer distances. First, they used the new laser to demonstrate the ability to transmit PAM4 225 Gb/s over a range of 5 km using the raw wavelength division multiplexing (CWDM) wavelength range under operating conditions at low temperatures. degree 50°C. They also use lasers to transmit PAM4 225 Gb/s at 1293.5 nm for a range of 10 km. This wavelength exhibits less chromatic dispersion than the wavelength range assigned to CWDM, the technology commonly used to send multiple optical signals simultaneously over a optical fiber. Color dispersion can cause optical signal degradation and cause more problems for longer transmission distances.

For all experiments, the new laser exhibits low-emitter and scattered-eye closure quaternions (TDECQ), indicating stable emitter performance. The researchers say that their results demonstrate the potential of the EA-DFB . composite electrode laser as a light source for 800G ethernet technology, covering 10 km applications. It can also be useful for CWDM4 applications longer than 5 km.

“Traffic in data centers is growing significantly year-on-year due to high-definition video streaming services, such as 4k and cloud applications. These results show EA Our DFB is a promising optical solution. light source to realize upcoming 800GbE applications,” said Nishimura.