OM4 can be shortlisted for compatible short-reach multimode optical links in an AI computing center. The OpticFiberHub reference lists effective modal bandwidth at 850 nm of ≥ 4700 MHz·km, attenuation of ≤ 2.4 dB/km at 850 nm, and a 50.0 ± 2.5 μm core. These values describe fiber on reels, not a complete GPU interconnect. Confirm the transceiver part number, supported fiber type, channel length, connector system and total loss allowance before specifying the cable. A published transceiver reach is specific to that optical system; OM4 bandwidth alone does not guarantee a data rate, distance or AI workload performance. Request the offered batch records and complete cable qualification evidence with your sourcing inquiry.
Where OM4 fits in an AI computing center
AI clusters connect compute nodes, network adapters and switches through a defined interconnect architecture. For routes using compatible short-reach multimode optics, OM4 is a fiber candidate to review. Corning identifies short-reach AI/ML and data center applications in its multimode fiber portfolio. This supports the application context; it does not establish that the OpticFiberHub grade has the same performance as a Corning product.
Review each route in the network plan rather than assigning one fiber grade to the whole facility. The link equipment and channel requirements determine whether the route uses multimode fiber, single-mode fiber or another interconnect. The recommendation here concerns optical links whose equipment explicitly supports OM4.
Match the OM4 reference to the optical interface
The specification table below uses the same six values as our OM4 product page. The 850 nm effective modal bandwidth is ≥ 4700 MHz·km. Retain the wavelength and bandwidth definition when comparing a requirement: this is not an Ethernet line rate and should not be substituted for a transceiver specification.
The reference also lists a 50.0 ± 2.5 μm core, 125 ± 1.0 μm cladding and 245 ± 7 μm coating. Coated-fiber diameter is different from a finished cable diameter. Confirm the offered fiber and the assembled cable specification together when planning dense rack pathways or cable manufacture.
Use transceiver reach as a specific example
NVIDIA documents its MMA4Z00-NS400 as a 400 Gb/s SR4 multimode transceiver using 850 nm VCSELs, with up to 50 m on OM4 and an MPO-12/APC optical interface. Its guide describes a particular equipment and connection arrangement. This is an example of an OM4-compatible short-reach system, not a 400 Gb/s or 50 m guarantee for the fiber sold on this site.
Confirm the actual part numbers and their current manufacturer requirements for your project. Check connector polish, fiber count, polarity and mating compatibility. Do not carry a reach figure from one optic into a different Ethernet or InfiniBand configuration without the corresponding system specification.
Build a complete channel loss budget
At 850 nm the listed fiber attenuation limit is ≤ 2.4 dB/km; at 1300 nm it is ≤ 0.6 dB/km. Use the value at the operating wavelength. For an illustrative 50 m length, 2.4 dB/km × 0.050 km gives 0.12 dB for the fiber contribution only. This arithmetic uses a reference limit, not a measured channel result.
Add the specified losses for connectors, splices and other components, plus the required design margin. Compare the complete channel against the selected optics and acceptance criteria. Routing and bend requirements come from the finished cable specification; the current OM4 table does not publish a minimum installation bend radius.
Prepare fiber, cable and acceptance requirements
For fiber sourcing, specify OM4, the required optical and dimensional limits, coating, total fiber-km, reel allocation and applicable batch documents. Keep these requirements separate from cable assembly details such as connector type and polarity, while recording how the finished assembly will be qualified.
For U.S. and European projects, have the cable supplier confirm the fire, installation and other compliance requirements applicable to the location. A coated-fiber reference does not certify a completed cable or assembly. Use the product page to review the full OM4 table and include the relevant specification and documentation requests in your RFQ.
| Parameter / condition | OM4 reference |
|---|---|
| Core diameter | 50.0 ± 2.5 μm |
| Cladding diameter | 125 ± 1.0 μm |
| Attenuation at 850 nm | ≤ 2.4 dB/km |
| Attenuation at 1300 nm | ≤ 0.6 dB/km |
| Effective modal bandwidth at 850 nm | ≥ 4700 MHz·km |
| Coating diameter | 245 ± 7 μm |
What to confirm
- Transceiver part numbers, protocol and supported fiber type
- Complete channel length and loss acceptance criteria
- 850 nm effective modal bandwidth and attenuation limits
- Connector system, polish, fiber count and polarity
- Finished cable routing, installation and compliance requirements
- Fiber quantity, coating, reel allocation and batch documents
Frequently asked questions
Does OM4 automatically support every AI cluster link?
No. Select fiber against the supported optics and complete channel requirements. OM4 is a candidate where the actual equipment specifies compatible multimode links; the facility label alone does not determine fiber type.
Does ≥ 4700 MHz·km guarantee 400 Gb/s over 50 m?
No. It is the listed effective modal bandwidth at 850 nm. The 400 Gb/s and 50 m example belongs to a named NVIDIA transceiver configuration. Confirm equipment compatibility, channel loss and acceptance separately.
Is this product a finished AI data center cable?
No. The OM4 product is coated optical fiber on reels. Finished cables and assemblies require separate construction, connector, installation and qualification specifications.
What documents should an OM4 inquiry request?
Request the offered specification, reel list and applicable batch optical and geometry records. Add any required bandwidth evidence and finished-cable acceptance documents to the project requirements.
Sources & reference context
This guide is published by OpticFiberHub and summarizes the supplier literature identified below with editorial purchasing guidance. Product values describe the source grade, not a measured result or a conformity guarantee for a new order.
- OM4 reference specifications — Jiangsu Nanfang Optical Fiber Product Manual, pages 15–16.
Application references
- NVIDIA MMA4Z00-NS400: 400 Gb/s multimode SR4 — A specific 850 nm OM4 transceiver and connection example; its reach is not a guarantee for the OpticFiberHub fiber reference.
- Corning: multimode fiber in short-reach AI/ML applications — Manufacturer application context. Corning product values and certifications are not attributed to this OM4 grade.
Quality & technical resources explains source selection, translated documents and the limits of historical batch records. Request the current specification and applicable records for the actual offered material.
Further terminology reference: The Fiber Optic Association: optical fiber fundamentals.
