How to use Ubiquiti SFP ports for fiber optic connections

SFP ports can be a bit of a mystery if you're not used to dealing with fiber in your network. But once you understand the basics, plugging fiber into your UniFi gear can be straightforward, and a huge upgrade for your setup. Whether you're running fiber between buildings or just want to boost bandwidth and distance over copper, Ubiquiti's SFP ports make this easier than you’d think.

This guide breaks down exactly how to use SFP ports on UniFi switches and gateways for fiber connections, what modules you’ll need, and a few real-world tips that’ll save you time and money.

Let's dive in !!

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What are SFP ports anyway?

SFP stands for "Small Form-Factor Pluggable." It's a type of interface found on many managed network switches, including a bunch of Ubiquiti UniFi gear.

These ports are designed to accept SFP modules, which can be either fiber or copper, and let you customize the uplink for your needs. You’ll find SFP ports on UniFi switches like the USW-24, USW-48, USW-Pro, and on certain gateways like the UDM Pro and UXG-Pro.

They come in two flavors: • SFP (1 Gbps) for gigabit connections • SFP+ (10 Gbps) for higher-speed links The port itself doesn't dictate the medium or the speed—the module you plug in does. That’s the whole point. It’s modular and flexible.

When should you use SFP ports?

There are a few common use cases where fiber over SFP is the right choice: • Linking distant switches: Fiber can run way longer than Ethernet. Cat6 tops out around 100 meters; fiber can go several kilometers. • Inter-building connections: Got another building across the lot? Trenching fiber between them is safer and more stable than trying wireless bridges. • High-bandwidth backbones: If you're pushing serious traffic between switches, fiber via SFP+ gives you 10G without breaking the bank. Choosing the right SFP module

This part trips up a lot of folks. Not all SFP modules are the same, and picking the wrong one can mean hours of troubleshooting. Here's what to look for:

1. Check compatibility

Ubiquiti sells their own branded modules like the UF-SM-1G-S, UF-MM-1G, UF-SM-10G, and others. These are plug-and-play with UniFi gear and tend to be the safest bet. That said, many third-party modules work just fine too, as long as they follow MSA (multi-source agreement) standards. Just know that support might not help you if something breaks. 2. Choose multimode or single-mode

This depends on the type of fiber you're using. • Multimode (MM): Good for shorter distances (up to 300m). Modules like UF-MM-1G or UF-MM-10G pair with orange or aqua LC cables. • Single-mode (SM): Handles much longer runs (up to 10km+). Modules like UF-SM-1G-S or UF-SM-10G use yellow LC cables. Don’t mix these up. MM and SM aren’t interchangeable. 3. Use matched pairs

When you're using modules at each end of a fiber cable, make sure they’re compatible. If you're using UF-SM-1G-S on one side, the other end needs to have the same or a compatible module. Some modules come in BiDi (bi-directional) pairs like UF-SM-1G-S and UF-SM-1G-L. These use a single fiber strand and send/receive on different wavelengths. It’s awesome for saving cable runs, but you need the correct send/receive pair. Connecting everything together

Once you have your modules and fiber in hand, the process is simple:

1. Insert the SFP modules into the SFP or SFP+ port of your UniFi device.
2. Plug in the fiber cable, LC connectors click right into the module.
3. Power on both devices.
4. Watch for a link light, if you see green, you're good. If not, double-check your cable type and module pairing.

In UniFi Network, you'll see the SFP port status under Devices > [Switch Name] > Ports. It should show up as “1000 Full” or “10G Full” depending on the module speed. Common issues and troubleshooting No link? • Make sure both ends are using the same type of module (SM or MM). • If you're using BiDi modules, ensure they’re the proper send/receive pair. • Check the cable—it might be damaged or bent too sharply. • Try a different port or reboot the switch. Unstable connection? • Double-check the fiber cleanliness. Use a proper cleaning kit—fiber is sensitive to dust. • Verify that the cable isn’t coiled too tightly. • Make sure the modules aren’t overheating in a crowded switch with poor airflow. SFP module not recognized? • Stick with Ubiquiti-branded modules for guaranteed compatibility. • Some older switches may not support certain SFP+ modules. • Firmware updates can sometimes fix recognition issues.

Real-world tip: Use DAC cables when possible

If you're connecting two switches sitting in the same rack, skip fiber altogether and go with a Direct Attach Copper (DAC) cable. These are SFP+ to SFP+ twinax cables that cost less and don’t require extra modules or fiber. Something like the Ubiquiti UDC-1 (1 meter) is perfect for short, 10G links between rack-mounted gear. Example setups

Example 1: Two buildings, 100 meters apart • Fiber cable: Single-mode LC-LC duplex • SFP module: UF-SM-1G-S in both switches • Switches: USW-24 in Building A, USW-Lite-16-PoE in Building B • Use case: Extending the network to a remote office with minimal latency and solid reliability

Example 2: 10G backbone in a server rack • Cable: Ubiquiti UDC-2 DAC cable • Switches: USW-Pro-48 and USW-Aggregation • Use case: High-speed link between core switches in the same rack

Example 3: Surveillance NVR on a fiber uplink • Fiber: Multimode 50/125 OM3 LC • SFP module: UF-MM-1G • Devices: USW-Pro switch in the server room and a UVC NVR mounted 150 meters away • Use case: Reliable camera storage traffic without burdening the copper infrastructure

Monitoring the connection The UniFi controller gives you live stats and link state info under each switch’s port details. You can: • See current speed (1G or 10G) • Monitor traffic in/out • Set port profiles for VLANs or tagging You can even configure failover uplinks or link aggregation if needed.

Conclusion

Using SFP ports on your Ubiquiti gear opens up a lot of options, especially when it comes to long-distance or high-speed links. Whether you're stretching your network between buildings or just need a clean 10G backbone, SFP and fiber is the way to go.

If you're hosting your UniFi Controller with us at UniHosted, you’ll already have all the tools and visibility you need to keep things running smoothly. Our hosted setup is perfect for managing large deployments with fiber interlinks, and we keep everything up to date behind the scenes, so you can focus on building out the network instead of babysitting it.