Multimode fiber color

Multimode fiber optic cables are color-coded to indicate their type: OM1 and OM2 are typically orange, OM3 and OM4 are aqua (with some OM4 in violet), and OM5 is lime green.

Standard Multimode Fiber Jacket Colors

• OM1 (62.5/125 µm): Orange jacket, commonly used with LED light sources for 100 Megabit Ethernet and short 10 Gigabit Ethernet links .
• OM2 (50/125 µm): Orange jacket, smaller core than OM1, supports 1–10 Gigabit Ethernet over moderate distances .
• OM3 (50/125 µm, laser-optimized): Aqua jacket, optimized for VCSEL laser transmission, supports 10 Gigabit Ethernet up to 300 meters and 40/100 Gigabit Ethernet up to 100 meters .
• OM4 (50/125 µm, laser-optimized): Aqua jacket (sometimes violet for differentiation), supports longer 10 Gigabit links up to 550 meters and 40/100 Gigabit Ethernet up to 150 meters .
• OM5 (50/125 µm, wideband multimode): Lime green jacket, designed for multiple WDM channels, supporting at least four 28 Gbps channels over 850–953 nm .

Historical and Connector Color Coding

Historically, multimode fibers were orange, black, or gray, while singlemode fibers were yellow . With the introduction of metallic connectors like FC and ST, color coding of the connector body became difficult, so colored strain relief boots are often used to indicate fiber type . For patch cords and connectors:

• OM1/OM2 multimode: Beige or orange connectors
• OM3/OM4 multimode: Aqua connectors
• OM4 (violet variant): Violet connectors for high-density differentiation
• OM5 multimode: Lime green connectors
• Singlemode UPC: Blue connectors
• Singlemode APC: Green connectors

Fiber Identification Inside Cables

Individual fibers within a cable are also color-coded according to the TIA/EIA-598-C 12-color sequence: Blue, Orange, Green, Brown, Slate (Gray), White, Red, Black, Yellow, Violet, Rose, and Aqua . For cables with more than 12 fibers, the sequence repeats with stripes to maintain unique identification. This system ensures correct splicing, patching, and network management.

Summary

Color coding in multimode fiber cables provides a quick visual reference for fiber type, core size, and connector compatibility. Orange indicates legacy OM1/OM2, aqua indicates OM3/OM4, violet may indicate OM4 in high-density setups, and lime green identifies OM5. Proper adherence to these standards reduces installation errors, simplifies maintenance, and ensures network reliability .