optical_io
by Andy Sun (achoenix@gmail.com)
Last update: 2025/10/04
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Optical Transceivers
Market
LightCounting Update
25Q2 update (25/06/12)
Notes
- 400G Ethernet modules declines as Amazon and Meta transition to higher speed
- Sales of 400G and 800G AOCs will also remain strong
- Alphabet, Amazon, Meta, Microsoft, and Oracle (in order) spend more in 25Q1 than 24Q1
- Oracle’s spending was up 233%, Q1 reached a record $5.6 billion
- Alibaba plans to invest $53 billion in AI infra over 3 years
- Tencent spent $3.7 billion 25Q1
800G market shares
Cignal AI 24/Q3 report (1/7/2025)
The transceiver use in datacenter
A comparision between cloud datacenter and AI datacenter from Shainer:
How the numbers might be estimated
| Cloud datacenter | AI datacenter | Note | |
|---|---|---|---|
| # of servers | 72k (73,728) | 72k (73,728) | |
| # of CPU/server | 1-2 | 1-2 | |
| # of GPU/server | 0 | 4 | |
| # of server/rack | 36 | 18 | NVL72 |
| # of racks | 2048 | 2048 | |
| scale-out bandwidth/server | 800 Gb/s | 800 Gb/s | |
| # of scale-out switch/rack | 1 | 1 | |
| # of scale-out transceiver/rack | 72 (36*2) | 72 (36*2) | 800G-link |
| total # of scale-out transceiver | 140K (147,456) | 140K (147,456) | clos topology |
| power /transceiver | 16W | 16W | 800G-DR OSFP [e.g. Coherent] |
| total power of scale-out transceivers | 2.36 MW | 2.36 MW | |
| scale-out bandwidth/server | 0 | 1.8 TB/s (18x800Gb/s) | GB-200 |
| # of scale-up switch (NV switch)/rack | 0 | 18 | GB200 [ref] |
| # of scale-up transceiver/rack | 0 | 1296 (36*18*2) | 800G-link |
| power /transceiver | 16W | 16W | 800G-SR LPO [e.g. ] |
| total # of scale-up transceiver | 0 | 2.65M (2,652,208) | full fat-tree topology |
| total power of scale-up transceivers | 0 | 42.5 MW |
Note:
- NVL72-GB200 NVLink network architecture
