News: Optoelectronics
7 June 2021
Lumentum presents lasers capable of transmitting at 224Gbps for 800 Gigabit Ethernet
With the massive proliferation of data-heavy services, including high-resolution video streaming and conferencing, cloud services infrastructure growth in 2021 is expected to reach a compound annual growth rate (CAGR) of 27%. Consequently, while 400 Gigabit Ethernet (GbE) is currently enjoying widespread deployment, 800GbE is poised to rapidly follow to address these bandwidth demands.
One approach to 800GbE is to install eight 100Gbps optical interfaces or lanes. As an alternative to reduce the hardware count, increase reliability and lower cost, a team of researchers at Lumentum Holdings Inc of San Jose, CA (which designs and makes photonic products for optical networks and lasers in industrial and consumer markets) has developed an optical solution that uses four 200Gbps wavelength lanes to reach 800GbE.
During a session at the Optical Networking and Communication Conference & Exhibition (OFC 2021) being held virtually on 6-11 June, Lumentum principal optical engineer Syunya Yamauchi is presenting the optimized design in the paper ‘224-Gb/s PAM4 Uncooled Operation of Lumped-electrode EA-DFB Lasers with 2-km Transmission for 800GbE Application’ on 8 June at 03:00 PDT (UTC – 07:00).
“Active optical devices are the most important components of optical communications systems,” says Mike Staskus, VP of Datacom product line management at Lumentum.
To achieve high-speed, high-bandwidth operations, Yamauchi’s team developed a lumped-element (LE) electroabsorption modulator-integrated distributed feedback (EA-DFB) laser capable of 2km transmission – a transmission length requirement for many modern large data centers – of 224Gbps signals operating over a wide temperature range.
“There are tradeoffs between high bandwidth and modulation characteristics, such as extinction ratio,” Staskus says. “We overcame the tradeoff by optimizing the design of EA-DFB using a simplified packaging method.”
Compared with a conventional EA-DFB, the LE EA-DFB’s reduced capacitance and inductance resulting from design and assembly optimizations in the EA modulator improves its power and bandwidth.
“It can enable the development of optical transceivers with twice the data rate of current 400GbE modules, without dramatic increases in the cost and power consumption, by using higher-speed laser transmitter chips that do not require power-hungry thermoelectric coolers,” says Staskus.
These results suggest that the LE EA-DFB could enable 800GbE applications, making this device a promising light source for future data-center applications.
“Next-generation lasers using this same ‘toolbox’ of advanced semiconductor and packaging processes may enable higher speeds, longer reaches and lower costs with the competitive levels of performance, reliability and power consumption,” says Staskus. “With the increase of various data streaming and other internet services, intra-data-center links will require higher speeds, including 1.6 terabits per second and beyond.”
