Solution · AI Data Center
400G and 800G Cabling: Choosing the Right MPO Link
Which connector, fiber type and polarity each 400G and 800G optic needs, and what that means for the trunks and cassettes you order.
Start from the optic
The transceiver decides the cabling. Parallel optics such as SR8 and DR4 send each lane on its own fiber, so they need MPO connectors. Duplex optics such as FR4 use a single LC pair.
| Optic (IEEE name) | Fiber | Typical reach | Connector | Fibers used |
|---|---|---|---|---|
| 400GBASE-SR8 | OM4 multimode | 100 m | MPO-16 APC | 16 |
| 400GBASE-DR4 | OS2 single-mode | 500 m | MPO-12 APC | 8 |
| 400GBASE-FR4 | OS2 single-mode | 2 km | Duplex LC | 2 |
| 800G 2×DR4 (twin-port OSFP) | OS2 single-mode | 500 m | 2× MPO-12 APC | 16 |
| 800G 2×SR4 | OM4 multimode | 50–100 m | 2× MPO-12 APC | 16 |
Reach and loss limits vary by module. Always check the datasheet of the exact transceiver you buy, and send us the part number with your request.
MPO-12 or MPO-16?
MPO-12
Most single-mode parallel links
DR4 and SR4 style optics use 8 of the 12 positions. Base-8 or Base-12 trunks are the common backbone.
MPO-16
SR8 multimode links
400G SR8 needs all 16 fibers in one connector. MPO-16 is keyed differently and does not mate with MPO-12.
Base-8 vs Base-12
Fiber use
With 8-fiber optics, Base-8 trunks use every fiber. Base-12 leaves 4 dark unless you convert in a cassette.
Read more: MPO-12 vs MPO-16 vs MPO-24 · MPO polarity Type A, B, C · 400G DR4, FR4 and LR4
Loss budget: fewer mated pairs
Higher speeds leave less margin for connector loss. Every mated pair between the two transceivers takes part of the budget, so plan the link before choosing products.
- Count every mated pair: patch panel, cassette, trunk ends, jumpers.
- Ask for low-loss (elite) MPO connectors on trunks with several mated pairs.
- Use APC (angled) MPO for single-mode parallel optics such as DR4.
- Keep polarity consistent across the channel; Type B trunks are common for parallel optics.
Send us the link layout and the transceiver part numbers. We check the fiber count, polarity and connector types and quote matching trunks, cassettes and jumpers.
Products for 400G/800G links
- MTP/MPO trunks for the backbone between rows
- MTP/MPO cassettes and high-density panels
- MTP/MPO jumpers for the last meter to the switch
- 400G/800G transceivers
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