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What Do OM1, OM3, OM4, OM5, and Singlemode Fiber Colors Mean?

  • Tom Damiano
  • • Published Jul 02, 2026
  • • Updated Jul 02, 2026

Fiber optic cable jacket colors provide a quick way to identify common fiber types used in network installations. Orange identifies OM1 multimode fiber with a 62.5/125 µm core/cladding size. Aqua represents OM3 or OM4 laser-optimized multimode fiber with a 50/125 µm core/cladding size. Lime green identifies OM5 multimode fiber, which also uses a 50/125 µm core/cladding size. Yellow indicates singlemode fiber with a 9/125 µm core/cladding size.

While jacket color is a helpful visual identifier, always verify the cable markings and product specifications before installation. If you're selecting a new assembly, explore our Pre-Terminated Fiber Optic Assemblies to find the right solution for your network.

Watch the Video

Watch the video to learn how to quickly identify OM1, OM3, OM4, OM5, and singlemode fiber by jacket color and understand what each color represents before selecting your next Pre-Terminated Fiber Optic Assembly.

Fiber Optic Cable Jacket Color Reference

Jacket Color Fiber Type Core/Cladding Size
Orange OM1 62.5/125 µm
Aqua OM3 or OM4 50/125 µm
Lime Green OM5 50/125 µm
Yellow Singlemode 9/125 µm

Frequently asked questions

Q1: What do OM1, OM3, OM4, OM5, and singlemode fiber colors mean?

Orange typically identifies OM1, aqua identifies OM3 or OM4, lime green identifies OM5, and yellow identifies singlemode fiber.

Q2: What color is OM1 fiber?

OM1 fiber is commonly identified by an orange jacket and uses a 62.5/125 µm core/cladding size.

Learn more about OM1 Fiber Optic Cables.

Q3: What color is OM3 fiber?

OM3 fiber typically uses an aqua jacket and has a 50/125 µm core/cladding size.

Browse our OM3 Fiber Optic Cables for high-speed multimode applications.

Q4: Is OM4 the same color as OM3?

Yes. Both OM3 and OM4 commonly use an aqua jacket, so always verify the cable markings to distinguish between them.

Explore our OM4 Fiber Optic Cables to compare available options.

Q5: What color is OM5 fiber?

OM5 fiber is commonly identified by a lime green jacket and uses a 50/125 µm core/cladding size.

See our OM5 Fiber Optic Cables for wideband multimode networking.

Q6: What color is singlemode fiber?

Singlemode fiber is commonly identified by a yellow jacket and has a 9/125 µm core/cladding size.

View our Singlemode Fiber Optic Cables for long-distance fiber deployments.

Q7: What is the difference between OM1, OM3, OM4, OM5, and singlemode fiber?

The primary differences are the fiber type, core size, and jacket color. OM1 uses a 62.5/125 µm core with an orange jacket, OM3 and OM4 use a 50/125 µm core with an aqua jacket, OM5 uses a 50/125 µm core with a lime green jacket, and singlemode fiber uses a 9/125 µm core with a yellow jacket.

If you're unsure which fiber type is right for your project, our Fiber Optic Cable Buying Guide can help you compare your options.

Q8: Can you identify fiber type by jacket color alone?

No. Jacket color provides a quick visual reference, but you should always verify the cable markings and product specifications before installation.

For additional guidance, visit our Fiber Optic Resource Center.

Q9: Why do fiber optic cable jacket colors matter?

Jacket colors help installers and network professionals quickly identify common fiber types during installation, maintenance, and troubleshooting, making deployments more efficient and reducing the risk of selecting the wrong cable.