13 Oct 2021
Consortium For On-Board Optics seeks ‘missing piece of the puzzle’ in development of board-level optical links.
A new working group set up by the Consortium For On-Board Optics (COBO) will try to establish optical waveguides as a viable technology for high-speed, board-level interconnects inside data centers.
Formally known as the Multi-Mode Waveguide Interconnect System (MWIS) Working Group, the industry partners will focus on increasing bandwidth and reducing power consumption for PCB (printed circuit board) interconnects.
The team will specifically work to replace conventional copper links with multi-mode waveguides, adding an extremely thin interface for electrical-to-optical and optical-to-electrical conversion in close proximity to electrical components.
Established in 2015 by some of the key players in the field - its founders include the likes of Cisco, Intel, and Microsoft - COBO has since created industry standards, completed demonstrations of optical links at the level of the PCB, and set up a similar working group focused on co-packaged optics.
Photonic component makers involved in the consortium include Finisar, now part of II-VI, Lumentum, and Mellanox Technologies.
Explaining the thinking behind the new working group, COBO’s president Brad Booth said: “The growing diversity of optical applications within the data center, including machine learning and resource disaggregation, are driving an increased need to enhance high-speed board level interconnect systems with optical waveguide technology.”
Booth, who is also principal engineer within the Azure Hardware Architecture division at Microsoft, invited any interested parties to contact COBO if they are interested in getting involved in the effort.
The new working group will be chaired by Joshua Kihong Kim, who is principal engineer at the Japan-headquartered electronic component maker Hirose Electric, also a vendor of fiber-optic connectors.
Kim said: “Although embedded optical waveguides in printed circuit boards have been researched for decades, now is the time for the industry to work together to address the imminent bandwidth and power issues associated with copper interfaces.
“In the development of on-board optical systems, this is one of the missing pieces of the puzzle, and COBO is stepping up to develop specifications to enable an industry ecosystem.”
Data center workload
Hyperscale data centers, which currently rely on high-performance lasers for the optical interconnects that connect different servers, have had to accommodate an ever-increasing data workload - something exacerbated by the widespread adoption of home-based working, education, and entertainment during the Covid-19 pandemic.
As a result, data centers are already estimated by the International Energy Agency (IEA) to account for around 1 per cent of global electricity demand, with the emergence of technologies like 5G connectivity, artificial intelligence, and blockchain applications like bitcoin mining further increasing that workload.
“Most of the world’s Internet Protocol traffic goes through data centers,” explained IEA in its June 2020 tracking report.
“Greater connectivity is therefore propelling demand for data center services and energy use (mostly electricity), with multiplying effects: for every bit of data that travels the network from data centers to end users, another five bits of data are transmitted within and among data centers.”
As IEA points out, despite that exponential rise in data traffic, the energy demands of data centers have essentially remained flat since 2010 - thanks to advances in the hardware and infrastructure, including optical links.
COBO’s MWIS working group aims to help maintain that trend, by extending the use of higher-efficiency optical links beyond server interconnects, and to the level of the PCB.