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Difference Between Optical Fiber OM1, OM2, OM3 and OM4

Issuing time:2019-04-09 08:52Author:Cocoon Lee

Difference Between Optical Fiber OM1, OM2, OM3 and OM4

"OM" stands for optical multi-mode, namely optical mode, which is the standard for multi-mode optical fiber to represent the optical fiber class. Different levels of transmission bandwidth and maximum distance are different from the following aspects to analyze the differences between them.

I. OM1, OM2, OM3 and OM4 fiber parameters and specifications

1. OM1 refers to 50um or 62.5um core diameter multimode fiber with full injection bandwidth of 850/1300nm and above 200/500mhz.km;

2. OM2 refers to 50um or 62.5um core diameter multimode fiber with full injection bandwidth of 850/1300nm and above 500/500mhz.km;

3. OM3 is a 50um core diameter multi-mode fiber optimized by 850nm laser. In 10Gb/s Ethernet using 850nm VCSEL, the optical fiber transmission distance can reach 300m;

4. OM4 is an upgraded version of OM3 multi-mode optical fiber, with optical transmission distance up to 550m.

Diameter (μm)
Fiber Type
1 Gigabit Ethernet 1000BASE-SX
1 Gigabit Ethernet 1000BASE-LX
10Gbps Ethernet 10GBASE
40Gbps Ethernet 40GBASE SR4
100Gbps Ethernet 100GBASE SR4
Not supported
Not supported
Not supported
Not supported
(Laser optimization)
(Laser optimization)
5km at 1310nm
5km at 1310nm
10km at 1310nm

II. Design comparison of optical fiber OM1, OM2, OM3 and OM4

1. Traditional OM1 and OM2 multi-mode optical fibers are based on the LED Emitting Diode in standard and design, while OM3 and OM4 are optimized on the basis of OM2 so that they are applicable for LD (Laser Emitting Diode) transmission at the same time.

2. Compared with OM1 and OM2, OM3 has higher transmission rate and bandwidth, so it is called optimized multi-mode fiber or multi-mode fiber.

3. OM4 is optimized on the basis of OM3 for better performance.

III. Comparison of functions and features of OM1, OM2, OM3 and OM4 optical fibers

1. OM1: large core diameter and numerical aperture, with strong light collecting ability and bending resistance;

2. OM2: both core diameter and numerical aperture are relatively small, effectively reducing the mode dispersion of multi-mode fiber, significantly increasing the bandwidth and reducing the production cost by 1/3;

3. OM3: flame retardant skin is adopted to prevent flame spread, smoke, acid gas and poisonous gas, etc. and meet the transmission rate of 10 GB/s;

4, OM4: developed for VSCEL laser transmission, twice more than the effective bandwidth of OM3.

difference between OM1, OM2, OM3 and OM4

IV. OM1, OM2, OM3 and OM4 optical fiber application comparison

1. OM1 and OM2 have been widely deployed in buildings for many years, supporting Ethernet transmission with a maximum of 1GB;

2, OM3 and OM4 cables are typically used in data center cabling environments to support 10G or even 40/100g high-speed Ethernet transmission.

V. When to use OM3 fiber patch cord?

OM3 fiber is a fiber designed to work with VCSEL and conform to the ISO/IEC11801-2nd OM-3 fiber specification to meet the requirements of 10 gigabit Ethernet applications.OM3 fiber has a variety of types, including indoor type, indoor/outdoor versatility, fiber core number from 4 to 48 cores. It also supports all applications based on the older multi-mode 50/125 fiber, including support for LED light sources and laser light sources.

1. The transmission distance of gigabit Ethernet can be extended to 900 meters using the OM3 optical fiber system, which means users do not need to use expensive laser devices when the distance between buildings is more than 550 meters.

2. Standard 62.5/125 m multimode fiber can be used for all conditions in the OC-12 (622Mb/s) rate range up to a distance of 2000 meters, except for single-mode fiber. However, the emergence of OM3 multi-mode optical fiber has changed this situation. Because OM3 optical fiber can improve the transmission distance of gigabit and 10-gigabit system, the optical module with 850nm wavelength and VCSEL will be the most cost-effective wiring scheme.

3. When the link length exceeds 1000 meters, single-mode fiber is still the only choice at present. Single-mode fiber can achieve a transmission distance of 5 kilometers on the wavelength of 1310nm in the gigabit system and 10 kilometers in the system.

4, when the link length is less than or equal to 1000 meters, OM3 50 m multi-mode fiber can be used in the gigabit system, and the single mode fiber should be used in the system.

5, when the link length is less than 300 meters, OM3 multimode fiber can be used in any gigabit and ten million system.

VI. When to use OM4 fiber patch cord?

For a typical link, the cost of a light module is approximately expensive. Although the cost of single-mode fiber is cheaper than that of multi-mode fiber, the use of single-mode fiber requires a very expensive 1300nm optical module, whose cost is about 2-3 times of 850nm multi-mode optical module. In general, the cost of a multi-mode fiber system is much lower than that of single-mode fiber system.

When investing in fiber cabling, if the initial investment of some cabling can be considered, the adoption of better multimode fiber, such as OM4 fiber, can ensure the full use of the current multimode fiber technology, reduce the overall cost of the current system. When the system needs to be upgraded to a higher speed system, such as 40G and 100G, OM4 can still be used and will be more cost saving.

In summary, when the transmission rate is greater than 1Gb/s, using multimode fiber is a good system choice. When the system needs higher transmission rate, the following are the guiding principles for us to choose OM4 optical fiber:

1.For Ethernet users, in the 10Gb/s system transmission, the transmission distance can be up to 300m to 600m. In 40Gb/s and 100Gb/s systems, the transmission distance is 100m to 125m.

2.For campus network users, OM4 fiber will support 4Gb/s fiber link length of 400m, 8Gb/s fiber link length of 200m or 16Gb/s fiber link length of 130m.


Multimode fiber technology has been developed from OM1 multimode to OM4 which now supports 10Gbps. This will enable users to get the most effective return on their investment and become the best option for backbone cabling or fiber to the desktop.

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