Difference between OM3 vs OM4 Fiber optic Cable: Differences, Advantages & Fiber Types Guide

If you are building or upgrading a data center, enterprise LAN, or high-density cabling system, you will definitely encounter OM3 and OM4 Fiber optic Cable. Both are popular laser-optimized 50/125μm multimode fibers, but they are not interchangeable. Choosing the wrong one will limit your network speed and transmission distance. In this guide, we will show you how to distinguish OM3 and OM4, their unique benefits, and other common Fiber optic Cable types available on the market.

What Is Fiber optic Cable? Quick Overview

Fiber optic Cable transmits data via light signals instead of electrical signals. Compared with copper cables, it features faster speed, longer transmission distance, anti-electromagnetic interference, and lower signal loss. Multimode Fiber optic Cable (OM series) is widely used for short-range high-speed connections inside data centers, server rooms and campus networks. OM3 and OM4 are the two most mainstream multimode grades.

How To Tell OM3 and OM4 Fiber optic Cable Apart

Many buyers mistakenly think they can only rely on jacket color, but this is not 100% reliable. Let’s check the core differences:

1. Modal Bandwidth OM3: 2000 MHz·km at 850nm OM4: 4700 MHz·km at 850nm, more than double the bandwidth of OM3
2. Transmission Distance at 10Gbps OM3 supports 10 Gbps up to 300 meters OM4 supports 10 Gbps up to 550 meters For 40G / 100G SR4 links, OM3 can run up to 100m, while OM4 can reach 150m
3. Jacket Marking & Color Standard OM3 jacket is aqua (turquoise). OM4 can be aqua or violet (Erika violet). Since some manufacturers also make OM4 with aqua jacket, always check the printed text on the cable outer sheath instead of judging only by color. The cable print will clearly mark OM3 or OM4.
4. Refractive Index Profile OM4 has a more optimized refractive index design to reduce modal dispersion, which is the root reason for its higher bandwidth and longer reach.

Advantages of OM3 Fiber optic Cable

OM3 is the first generation of laser-optimized multimode Fiber optic Cable. Its biggest strength is balanced cost and stable performance.

• Lower cost than OM4, great for budget-sensitive projects
• Mature and widely stocked, easy to source patch cords and trunk cables
• Fully supports 10G, 40G short-distance links
• Compatible with existing 10G SR transceivers Perfect choice for small data centers, office internal networks, and links shorter than 300 meters.

Advantages of OM4 Fiber optic Cable

OM4 is the upgraded version of OM3 Fiber optic Cable, designed for higher-density and faster-speed networks.

• Much higher modal bandwidth and longer transmission distance
• Better headroom for future network upgrades to 40G, 100G
• Less signal attenuation under high-speed transmission
• Ideal for high-density MTP/MPO trunk cabling in large data centers If you plan to upgrade your network within a few years, OM4 avoids re-cabling and saves long-term labor costs.

Other Common Types of Fiber optic Cable

Besides OM3 and OM4, there are more multimode and single-mode Fiber optic Cable options you need to know:

• OM1: Legacy 62.5/125μm multimode, orange jacket, mainly for old low-speed networks, not recommended for new 10G builds
• OM2: 50/125μm older multimode, orange jacket, low bandwidth, only for 1G and below
• OM5: Wideband multimode fiber, lime green jacket. It supports SWDM4 wavelength division multiplexing, allowing 40G/100G over the same fiber pair, the newest multimode option for modern data centers
• OS1 / OS2 Single-mode Fiber optic Cable: Yellow jacket, ultra-long transmission distance, used for campus backbone, FTTH, and long-haul telecom links, supporting 10G, 40G, 100G and even 400G for kilometers.

Final Tips for Selecting Your Fiber optic Cable

For short-distance, cost-controlled 10G links under 300m, OM3 works well. If you need longer reach, 40G/100G deployment or future-proofing, OM4 is the safer pick. OM5 is suitable if you want to maximize fiber core usage with SWDM technology. Always match fiber grade, transceivers and connectors in your whole cabling system.

With all these specs and differences in mind, will you choose OM3, OM4 or OM5 for your next data center cabling project?