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November 28, 2021
"OM" means "Optical Multi-mode", which is a standard for multimode fiber to indicate fiber grade. Currently, the optical fiber patch cord standards defined by TIA and IEC include OM1, OM2, OM3, OM4, and OM5.
What are multi-mode and single-mode? Single Mode Fiber (SMF) is an optical fiber that allows only one mode of transmission, with a core diameter of about 8-9μm and an outer diameter of about 125μm. Multimode Optical Fiber（MMF） allows different modes of light to be transmitted on a single fiber, with a core diameter of 50μm and 62.5μm. Compared with multi-mode fiber, single-mode fiber can support longer transmission distance. From 100Mbps Ethernet to 1G Gigabit network, single-mode fiber can support transmission distance of more than 5000m. Multimode optical fiber is only suitable for short- and medium-distance and small-capacity optical fiber communication systems, such as campus networks, corporate LANs, and data centers.
Difference between OM1, OM2, OM3, OM4 and OM5 multimode fiber
|Fiber Types||Core Diameter||Color of Outer Sheath||Application|
1. OM1 fiber uses LED light source, the core diameter is 62.5μm, and the outer sheath is usually orange. OM1 has been widely deployed in building applications for many years and supports Ethernet transmission with a maximum of 1GB. Due to the large diameter of the OM1 core, it has strong light collection and bending resistance.
2. OM2 fiber uses LED light source, the core diameter is 50μm, and the outer sheath is usually orange. OM2, like OM1, is also widely deployed in building applications and supports Ethernet transmission with a maximum of 1GB; Compared with OM1 fiber, the core diameter of OM2 fiber is reduced, which effectively reduces the modal dispersion of the multimode fiber, which increases the bandwidth and reduces the production cost.
3. OM3 fiber is a kind of laser optimized multimode fiber. This type of fiber uses 850nm VCSEL laser light source, the core diameter is 50μm, and the outer sheath is aqua blue. It is usually used in the wiring environment of data centers and supports 10G or even It is a 40/100G high-speed Ethernet transmission. Compared with OM1 and OM2 fibers, OM3 has a higher transmission rate and bandwidth, so it is also called optimized multimode fiber or 10 Gigabit multimode fiber.
4. OM4 fiber is an upgraded version of OM3 multi-mode fiber with superior performance. For example, the effective bandwidth of OM4 fiber is more than double that of OM3 fiber, and it is compatible with OM3 fiber, and the outer sheath is aqua blue or violet. In the wiring of 40/100G high-speed data center, OM4 fiber has a longer transmission distance than OM3 fiber, which can reach 400 meters.
5. OM5 fiber is called wideband multimode fiber jumper (WBMMF), which is a laser-optimized multimode fiber (MMF), which has bandwidth characteristics specified for wavelength division multiplexing (WDM), and the outer sheath is water green. The purpose of this new fiber classification method is to provide support for a variety of "short" wavelengths between 850nm and 950nm. The wavelengths in this range are suitable for high-bandwidth applications after aggregation and are suitable for data centers with larger link distances. . The OM3 and OM4 are designed to support a single wavelength of 850nm.
With the increasing demand for high-speed network applications, multimode optical fiber is moving in the direction of low loss, high bandwidth and multi-wavelength multiplexing. Compared with OM1/OM2/OM3/OM4 multimode fiber, OM5 multimode fiber has high scalability and flexibility, can support higher speed network transmission with fewer cores, and its cost and power consumption are much lower. For single-mode fiber. It can be seen that in the future, OM5 multimode fiber may be widely used in 100G/200G/400G ultra-large data centers.