Multimode fiber is widely used in local area networks (LANs), data centers, and enterprise environments due to its cost-effectiveness and performance. Among various fiber types, the most common categories are OM1, OM2, OM3 fiber, OM4, and OM5, with OM3 fiber being especially popular for high-speed data transmission in modern network systems.
1. What is multimode fiber?
The common varieties of multimode fiber are known as OM3 fiber. These refer to types of optical fiber that allow transportation of more than one light path or mode through the core at the same time. It is mainly used for much shorter distances in relation to single-mode fiber. The multimode fiber carries more light at a core diameter ranging from 50 μm to 62.5 μm and is hence considered ideal for high-volume data transmission in buildings, campuses, and data centers.
2. How many types of multimode fiber are there?
Five major types of multimode fiber include, but are not limited to, the following: OM1, OM2, OM3, OM4, and OM5. Each of them was developed to meet ever-increasing demands for speed and efficiency in data transmission. Here are short descriptions and main characteristics of each:
（1） OM1 – The Basic Type
One type of multimode fiber is called OM1, with a 62.5-μm core, where the light source used is an LED; applications are for short-distance, low-speed networks.
Key Points:
- Gbps up to 275 meters
- Common in LAN and building cabling
- Low cost, easy to be installed.
（2） OM2 — The Improved Version
Instead, OM2 uses a 50-micron core to support even better light transmission at longer communication distances compared to OM1.
Key Points:
- Gbps up to 550 meters
- Ideal for campus or office networks
- Medium performance LED light sources
（3）OM3 – The Laser-Optimized Fiber
The fiber OM3 is optimized for VCSEL laser sources. It provides higher bandwidth and speed, and it generally is the most common choice for modern data centers and enterprise systems.
Supports:
- 10Gbps up to 300 meters
- Compatible with 40/100 Gbps short links
- It balances the cost, speed, and stability properly.
（4）OM4 – The High-Performance Option
The OM4 represents an extended version of the OM3 fiber, going to longer distances within the link, and increased stability for high-speed applications.
Key Points:
- Supports 10 Gbps up to 550 meters
- Supports 40/100 Gbps up to 150 meters
- Suitable for large-scale network backbones
（5）OM5 – The Next Generation Fiber
Because OM5 fiber is intended for use in multi-wavelength transmission and will be applied in future data center systems, the fiber is also called wideband multimode fiber.
Key Points:
- Operates within the wavelength range of 850-953 nm
- Supports 40/100/400Gbps transmission
- Allowing more data channels within one fiber
3. OM1 vs. OM2 vs. OM3 vs. OM4 vs. OM5: What’s the Difference?
The difference can be made more distinct by tabulating major parameters and applications for each type of multimode fiber, as in the table below.
Fiber Type Core Diameter Typical Light Source Maximum Data Rate Maximum Distance (10 Gbps) Common Application
| OM1 | 62.5 μm | LED | 1 Gbps | 275 m | LAN / Office Networks |
| OM2 | 50 μm | LED | 1 Gbps | 550 m | Campus Networks |
| OM3 | 50 μm | VCSEL laser | 10 Gbps | 300 m | Data Centers |
| OM4 | 50 μm | VCSEL Laser | 10–40 Gbps | 550 m | Enterprise Networks |
| OM5 | 50 μm | VCSEL Laser | 40–400 Gbps | 150 m | Advanced Data Centers |
Due to their effective balance between performance and cost, OM3 and OM4 fibers find applications in practically all the high-speed communication systems today.
4. What is the difference between single-mode and multimode fiber?
While both are optical fibers, the single mode and multi-mode differ in the transmission of light.
（1） Single-Mode Fiber
Has a 9-μm core; transmits light in a single path
This, in turn, can allow for the possibility of very ultra-long-distance transmissions, exceeding even 40 km normally used for telecommunication and intercity networks.
（2） Multimode Fiber
It contains a core of 50–62.5 μm to allow several light paths. Ideal for short-distance communication within buildings and on campuses. Smaller and lighter than single-mode fiber; easier to handle and install.
In other words, single-mode fiber is better for long-distance and high-capacity networks while multimode fibers, especially OM3 fibers, are applicable to shorter or high-speed internal networks.
5. Advantages of Multimode Fiber
- Cost-Effective: Multimode fibers tend to be cheaper in the cost of both the cable and transceivers. Installation is also easier, hence lower labor costs.
- High Speed for Short Distance: In fact, they can carry up to 100 Gbps within 100–150 meters, enough for most enterprise or campus setups.
- Easy Integration: Multimode systems, especially with OM3 fiber, can easily be integrated with existing network devices and, at the same time, support future upgrades.
Conclusion
The right type of multimode fiber will depend on network size, data rate, and budget. For smaller networks, either OM1 or OM2 should be adequate, but in fact, modern systems find an ideal balance between speed, performance, and scalability on OM3 fiber and OM4. Multi-wavelength transmission is supported on OM5 for future-ready networks.OMC provides high-quality fibers characterized by excellent durability to provide reliable fiber solutions, stable transmission, and high compatibility, meeting current and next-generation network demands.
