The IEEE P802.3db 100 Gb/s, 200 Gb/s, and 400 Gb/s Short Reach Fiber Task Force has completed its last draft, with no changes or new negative votes put forth by the deadline last week. The standard, which covers high-speed interconnect requirements over 50 and 100 m of multimode fiber, is now two steps away from IEEE SA Standards Board approval, which the Task Force vice chair said he hopes the standard will receive this September. Meanwhile, industry has already moved to begin development of the technology necessary to enable even higher transmission rates than those covered in this impending standard.
The standard will cover VCSEL-based duplex 100G-per-lane transmission over short reach (SR) distances of up to 100 m and very short reach (VR) requirements of up to 50 m on OM4 and OM5 multimode fiber. The objectives of the Task Force include:
- 100G over one pair of MMF up to at least 50 m
- 200G over two pairs of MMF up to at least 50 m
- 400G over four pairs of MMF up to at least 50 m
- 100G over one pair of MMF up to at least 100 m
- 200G over two pairs of MMF up to at least 100 m
- 400G over four pairs of MMF up to at least 100 m.
According to IEEE P802.3db Task Force Vice Chair Mabud Choudhury of OFS (who, like all who contribute to IEEE standards activities, participated as an individual rather than as a representative of his employer), the SR applications will use 850-nm VCSELs, while the VR specifications allow a wider spectrum range, from 850 to 940 nm. The specifications will help enable VCSEL-based high-speed multimode links for enterprise and hyperscale data center requirements; experts from Alibaba and Google have provided input on hyperscale data center requirements and use cases, Choudhury said, while several other experts presented information related to enterprise data center requirements.
With the successful completion of the second Standards Association (SA) recirculation ballot, Draft 3.2 of the standard will now move to potential IEEE RevCom approval in September. Assuming success at that stage, final approval is expected this September as well, which would be right on time based on the timeline approved by the Task Force in 2021. Choudhury cited the participation of industry experts as well as the work of Task Force Chair Robert Lingle of Georgia Tech Research Institute (and formerly OFS) and co-editors Ramana Murty of Broadcom and Earl Parsons of CommScope as instrumental in achieving the progress so far.
MSA thinks ahead
With work on multimode SR and VR specifications for rates up to 400 Gbps nearing completion, the IEEE has begun work on the next transmission step. The P802.3df 200 Gb/s, 400 Gb/s, 800 Gb/s and 1.6 Tb/s Ethernet Task Force is set to create similar specifications for 100G/lane SR and VR over multimode at 800 Gbps (see “Ethernet’s Next Rates – 800 Gb/s and 1.6 Tb/s”). As is often the case, industry multi-source agreements (MSAs) have formed ahead of the specification work. The Terabit Bidirectional (BiDi) MSA announced this past February that it will strive to speed development of technologies for such 800 Gigabit Ethernet applications as well as 1.6 Terabit Ethernet (see “Terabit BiDi MSA targets 800G, 1.6T over data center multimode fiber”). II-VI, Alibaba, Arista Networks, Broadcom, Cisco, CommScope, Dell Technologies, HG Genuine, Lumentum, MACOM, and Marvell Technology are the founding members.
[Some points in this article have been updated from the original based on input from IEEE sources.]
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