An Active Optical Cable (AOC) is a fiber optic cable with integrated transceiver electronics permanently attached at both ends. Unlike traditional transceivers that plug into a switch and then connect to a separate fiber patch cord, an AOC is a single integrated assembly. For network engineers designing 25G, 100G, 400G, and 800G links, AOC cables offer a specific performance and cost profile that makes them the right choice in certain scenarios — and the wrong choice in others.
How Does an AOC Cable Work?
Each end of an AOC contains a VCSEL (Vertical-Cavity Surface-Emitting Laser) transmitter and a photodetector receiver, bonded directly to the cable. Electrical signals from the switch or NIC port are converted to optical signals at one end, transmitted over multimode fiber, and converted back to electrical signals at the other end.
Because the optics are integrated, the host device sees the AOC as a standard pluggable transceiver (SFP+, QSFP28, QSFP-DD, etc.) — no special driver or configuration is needed.
AOC vs DAC vs Optical Transceiver: Comparison Table
| Parameter | AOC Cable | DAC Cable | Transceiver + Fiber |
|---|---|---|---|
| Signal Type | Optical (multimode) | Electrical (copper twinax) | Optical (SM or MM) |
| Distance Range | 1m to 100m | 0.5m to 5m | Up to 40km (SM) |
| Power Consumption | Medium (1.5-3W) | Low (<2W) | Variable (1-5W) |
| Flexibility | High (thin, light) | Low (stiff, heavy) | Moderate |
| Field Reconfigurable | No (fixed ends) | No (fixed ends) | Yes |
| Typical Cost (100G) | Medium | Lowest (<3m) | Highest (SM) |
| Best Use Case | 5m-100m rack-to-rack | Within-rack (<3m) | Inter-building/long reach |
AOC Cable Speeds and Form Factors
| Speed | Form Factor | Max Distance | Common Use |
|---|---|---|---|
| 25G | SFP28 | 100m | Server to ToR switch |
| 100G | QSFP28 | 100m | Leaf-spine uplinks |
| 200G | QSFP56 | 70m | High-density spine links |
| 400G | QSFP-DD / OSFP | 70m | AI cluster fabric |
| 800G | QSFP-DD 800 / OSFP | 50m | Next-gen GPU clusters |
| 100G (breakout) | QSFP28 to 4xSFP28 | 30m | Top-of-rack breakout |
When to Choose AOC Over DAC
Choose AOC when your link distance is between 3m and 100m. At this range, DAC cables are not available (copper twinax cannot reliably carry high-speed signals beyond 5m), and pluggable transceivers with separate fiber patch cords add complexity. AOC delivers the simplicity of a single-cable assembly with optical performance.
AOC is also preferred when cable weight and bend radius matter — in dense, cabled racks with many cross-connects, the thin flexible jacket of an AOC reduces cable management complexity compared to copper DAC cables.
FAQ
Q: Can I plug an AOC cable into any switch with the matching transceiver port?
A: Yes, with one caveat: some switches enforce vendor lock-in and reject third-party transceivers. Most Cisco, Arista, Juniper, and Nvidia switches accept OEM-compatible AOC cables when the transceiver firmware is coded for that platform. Always specify the target switch when ordering.
Q: What fiber type is inside an AOC cable?
A: Almost all AOC cables use OM3 or OM4 multimode fiber. OM4 is the current standard for 100G-800G AOC, supporting longer distances. Single-mode AOC exists but is uncommon and expensive — regular transceivers with SM patch cords are more practical for long distances.
Q: Can an AOC cable be repaired if one end is damaged?
A: No. AOC cables are not field-repairable. The transceivers are factory-bonded to the fiber. If either end is damaged, the entire cable must be replaced. This is why it is important to order AOC cables in confirmed, measured lengths — unlike patch cords, you cannot trim or re-terminate them.
Q: What is the typical lead time for custom-length AOC cables?
A: Standard lengths (1m, 3m, 5m, 10m, 30m) are usually in stock. Custom lengths (e.g., 7m, 15m) require 10-15 business days for production. For orders over 200 units, plan 20-25 business days with an additional 5-7 days for air freight.
Q: How do I verify an AOC cable is working correctly after installation?
A: Use the switch CLI to check optical Tx/Rx power. For Cisco: show interface transceiver. For Arista: show interfaces transceiver detail. Rx power should be within the receiver sensitivity range specified in the datasheet (typically -10 to -1 dBm for 100G AOC).
ABPTEL offers AOC cables from 25G SFP28 to 800G QSFP-DD in standard and custom lengths, with compatibility coding for major platforms. Request a quote or sample for your project.
Talk to ABPTEL
Looking for the right optical hardware for your AI data center, GPU cluster, or FTTA project? ABPTEL ships from Shenzhen with OEM/ODM support, fast lead times, and engineering-level pre-sales advice.
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- 🧩 SFP / SFP+ / SFP28 / QSFP28 Modules — 1G to 100G optical transceivers
- 📋 Data Center Cabling Solutions — end-to-end design guide
- ❓ Read our FAQ — compatibility, polarity, lead time, MOQ
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