OM3 (Optical Multimode 3) and OM4 (Optical Multimode 4) are types of optical fibers used in data transmission and networking applications. These fibers are designed to carry multiple signals, such as data, over short to medium distances within a network. This post will illustrate the detailed comparison of OM3 vs OM4 in six aspects and explain some capabilities of OM3 and OM4.
OM3 fiber typically has a specified minimum modal bandwidth of 2000 MHz·km at 850 nm (nanometers), which is the wavelength commonly used for multimode fiber transmissions in data center and LAN applications.This bandwidth is suitable for supporting high-speed data rates such as 10 Gigabit Ethernet (10GbE) at lengths of up to 300 meters and 40 Gigabit Ethernet (40GbE) at lengths of up to 100 meters. While OM4 fiber offers a higher minimum modal bandwidth than OM3, typically around 4700 MHz·km at 850 nm. This increased bandwidth allows OM4 fiber to support higher data rates and longer distances compared to OM3. For example, it can support 100 Gigabit Ethernet (100GbE) at lengths of up to 150 meters.
OM3 fiber is capable of supporting the following data rates at common wavelengths:
• 10 Gigabit Ethernet (10GbE) at lengths of up to 300 meters using 850 nm wavelength.
• 40 Gigabit Ethernet (40GbE) at lengths of up to 100 meters using 850 nm wavelength.
• 100 Gigabit Ethernet (100GbE) at lengths of up to 100 meters using multiple wavelengths and parallel optics.
OM4 fiber generally supports higher data rates at longer distances compared to OM3 fiber. It can support:
• 10 Gigabit Ethernet (10GbE) at lengths of up to 550 meters using 850 nm wavelength.
• 40 Gigabit Ethernet (40GbE) at lengths of up to 150 meters using 850 nm wavelength.
• 100 Gigabit Ethernet (100GbE) at lengths of up to 150 meters using multiple wavelengths and parallel optics.
• 400 Gigabit Ethernet (400GbE) at lengths of up to 100 meters using multiple wavelengths and parallel optics.
The transmission maximum distance of OM3 and OM4 fiber cables varies when they are applied to Gigabit, 10GbE, 40GbE and 100GbE applications. Here is the the maximum transmission distances of OM3 and OM4 under different transmission speeds in the below figure.
| Type | Fiber Type | Core Diameter Size （μm） | 1G Ethernet | 10G Ethernet | 40G Ethernet | 100G Ethernet |
| OM3 | Multimode | 50/125 | 550m | 300m | 100m | 100m |
| OM4 | Multimode | 50/125 | 550m | 400m | 150m | 150m |
Obviously, the OM310g distance and 40g 100g distance are shorter than OM4. In summary, OM4 fiber generally offers longer maximum distances compared to OM3 fiber across a range of common data rates, making it better suited for applications where extended reach and high-speed data transmission are necessary.
OM3 fiber is suitable for applications with shorter reach and lower bandwidth requirements such as data centers for connecting servers, Local Area Networks (LANs)，Gigabit Ethernet (1GbE) and Fiber Channel applications. Whereas, OM4 fiber is designed for applications demanding higher bandwidth and longer reach, particularly in data centers and enterprise networks where high-speed data transmission is critical. It can be used in Data Centers, Enterprise Networks, 40 Gigabit and 100 Gigabit Ethernet, Parallel Optics and 400 Gigabit Ethernet.
The color coding for OM3 and OM4 fibers is the same because both types of fibers share the same core diameter (50 micrometers) and use similar wavelength specifications. OM3 fiber is commonly identified by its aqua or turquoise-colored jacket. The aqua color is a standard industry practice for OM3 multimode fibers and is often used to distinguish them from other types of optical fibers. The color for OM4 fiber is the same as OM3, which is usually aqua or similar shades of blue-green. It's important to note that the color coding is an industry convention, and the actual color may vary slightly depending on the manufacturer or specific cable design, but aqua or similar shades are the most common.
The cost difference between OM3 and OM4 optical fibers can vary depending on several factors, including market demand, availability, and specific product offerings from manufacturers. In general, OM4 optical fibers are typically more expensive than OM3 fibers due to their superior performance characteristics. It's important to note that pricing can vary significantly between manufacturers and suppliers, and market conditions can change over time. Therefore, it's advisable to obtain quotes and compare prices from different suppliers when considering OM3 or OM4 fiber products for a specific project. Additionally, consider the specific performance requirements of your network to determine whether the enhanced performance of OM4 fibers justifies the higher cost for your application.
In many cases, especially for short-distance connections at lower data rates, OM3 and OM4 fibers can be used interchangeably without significant issues. However, it's essential to consider your specific network requirements and compatibility with existing components when making a choice. If you are unsure about which fiber type to use, consulting with a network engineer or fiber optics specialist can help you make the best decision for your particular application.
OM3 and OM4 optical fibers are generally backward compatible with older multimode fiber types, such as OM1 and OM2 fibers. However, the compatibility and performance may depend on various factors, including the specific optical components, light sources, and distances involved. It's important to conduct thorough testing and consider the specific performance requirements of your network when implementing backward compatibility between different fiber types.
Yes, it is possible to mix OM3 and OM4 fibers in the same network, but keep in mind to ensure that the connectors on your OM3 and OM4 fiber components are compatible and can be mated together and the transceivers used in your network should be compatible with both OM3 and OM4 fibers.
Choosing OM4 over OM3 optical fibers can provide future-proofing benefits for your network infrastructure, especially in scenarios where higher data rates and longer distances may be required in the future. OM4 fibers offer significantly higher bandwidth compared to OM3 fibers, and they are more likely to meet the requirements of these emerging standards without the need for extensive infrastructure upgrades. By choosing OM4 fibers from the outset, you can minimize the need for future fiber upgrades and maintenance, reducing downtime and associated costs.
