Differences between OS1, OS2, & OM1, OM2, OM3, OM4, and OM5 fiber optic cables


1. What are OM and OS fiber optic cables? 
Optical fibers can be divided into single-mode and multi-mode according to the transmission mode of light in them. OS type is for single-mode fiber, and the OMx standard is only for multimode fiber.

OS VS OM fiber

1.1 What is OS type fiber optic cables? 
OS-type fiber optic cables, also known as single-mode fibers, contain a very thin core of about 5-10 micrometers (millionths of a meter) in diameter. All signals go straight from the middle without bouncing around the edges.

1.2 What is OM type fiber optic cables?
In OM-type fiber optic cables, also known as multimode fiber optic cables, each fiber is about 10 times the size of a single-mode fiber. This means that the beam can pass through the core in a variety of different patterns (yellow, orange, blue and cyan lines).

Because multimode fiber optic cables spread the light propagating with the core into multiple paths, it allows for higher bandwidth over short and medium distances. However, in long cable operations, multiple optical paths can cause distortion at the receiving end, resulting in unclear and incomplete data transmission.

2. What are the differences between OM and OS-type cables?
OS-type cable has the simplest structure, it can be divided into OS1 and OS2, their main difference lies in the cable structure rather than the optical specification. OS1 cables are of tightly buffered construction, while OS2 cables are of loose tube or blown cable construction.

OM-type cables are typically only used for short-range applications such as data centers. The types of multimode fiber optic cables are generally divided into OM1, OM2, OM3, OM4, and OM5. The main difference is that different grades of OM cables have different bandwidths and maximum distances.

3. Comparison between different types of OS fiber optic cables

OS fiber

3.1 OS1 single mode tightly buffered cable

Each OS1 fiber has its own double protective coating, one plastic and the other waterproof acrylic. This tightly buffered cable features a smaller, lighter-weight cable that is more flexible and more resistant to crushing than the loose tube. Installation is easier since there is no gel to clean and no connector terminals for fan-out components.

Application: OS1 single-mode fiber can support speeds up to 10G and distances up to about 10 kilometers (6 miles). It is mainly used indoors such as mid-distance telco local loops, LANs and point-to-point links in cities, buildings, factories, office parks or campuses.

 3.2 OS2 single mode loose tube cable
Except for the outer coating, all fibers of the OS2 are basically bare, and each fiber has a colored coating for identification. In addition, the fiber “floats” in a strong, wear-resistant, oversized tube, which is often filled with an optical gel to protect the fiber from moisture. Connector terminals require fan-out components.

Application: OS2 single-mode loose tube cable can support speeds up to 100G and distances up to 200 kilometers (124 miles). It is widely used in outdoor applications such as long-distance telecom backbone and backhaul lines, direct burial applications along streets and railways.

3.3 Summary of OS-type cables (Single mode fiber)
Single-mode fiber is the standard choice for high data rates or transmission over long distances. Compared to multimode fiber optic cables, single mode fiber can transmit signals at higher speeds with less signal attenuation and external interference.

4. Comparison between different types of OM fiber optic cables

OM fiber

4.1 Parameters and Specifications

  • OM1 refers to 50um or 62.5um core diameter multimode fiber with 850/1300nm full injection bandwidth above 200/500MHz.km;
  • OM2 refers to 50um or 62.5um core diameter multimode fiber with 850/1300nm full injection bandwidth above 500/500MHz.km;
  • OM3 is a 50um core diameter multimode fiber optimized by 850nm laser. In 10Gb/s Ethernet using 850nm VCSEL, the fiber transmission distance can reach 300m;
  • OM4 is an upgraded version of OM3 multimode fiber, and the fiber transmission distance can reach 550m;
  • OM5, the latest multimode fiber, is designed to support Short Wavelength Division Multiplexing (SWDM), capable of 40 Gb/s and 100 Gb/s.

Comparison of transmission distance between single-mode fiber and multi-mode fiber

Fiber Type1000Base/1Gb(SX)Ethernet1000Base/1Gb(LX)Ethernet10Gb Ethernet40Gb Ethernet100Gb Ethernet
OS1/OS2 single mode fiber(1310nm)5Km20Km40Km40Km80Km
OM1 multimode fiber(850nm)275m550m33m//
OM2 multimode fiber(850nm)550m550m82m//
OM3 multimode fiber(850nm)550m550m300m100m100m
OM4 multimode fiber(850nm)550m550m550m150m150m
OM5 multimode fiber(850nm)//550m440m150m

4.2 Design

  • The traditional OM1 and OM2 multimode fibers are based on LED (Light Emitting Diode) light sources in terms of standard and design, while OM3 and OM4 are optimized on the basis of OM2, making them suitable for the transmission of LD (Laser Diode) as the light source at the same time;
  • Compared with OM1 and OM2, OM3 has higher transmission rate and bandwidth, so it is called optimized multimode fiber or 10 Gigabit multimode fiber;
  • OM4 is re-optimized on the basis of OM3, with better performance.
  • OM5 fiber is built on the basis of OM3/OM4 fiber and expands its performance to support multiple wavelengths. The original intention of OM5 fiber design is to meet the wavelength division multiplexing (WDM) requirements of multimode transmission systems

4.3 Functions and Features

  • OM1: The core diameter and numerical aperture are large, and it has strong light-gathering ability and bending resistance;
  • OM2: The core diameter and numerical aperture are relatively small, which effectively reduces the modal dispersion of the multimode fiber, significantly increases the bandwidth, and reduces the production cost by 1/3;
  • OM3: The flame retardant outer skin can prevent the spread of flames, prevent the emission of smoke, acid gas and poisonous gas, etc., and meet the needs of 10Gb/s transmission rate;
  • OM4: Developed for VSCEL laser transmission, the effective bandwidth is more than double that of OM3;
  • OM5: Only 8-core Broadband Multimode Fiber (WBMMF) is required to support 200/400G Ethernet applications; support up to 150 meters in length with the same transceiver.

OM fiber optic


  • Color – orange
  • Core Size – 62.5um
  • Data Rate – 1GB @ 850nm
  • Distance – up to 300 meters
  • Applications – short-range networks, local area networks (LANs) and private networks


  • Color – orange
  • Core size – 50um
  • Data Rate – 1GB @ 850nm
  • Distance – up to 600 meters
  • Typically used for shorter distances; 2x distance capacity of OM1
  • Applications – short-range networks, local area networks (LANs) and private networks

OM3 (Laser Optimized Multimode)

  • Color – Aqua
  • Core size – 50um
  • Date Rate – 10GB @ 850nm
  • Distance – up to 300 meters
  • Uses fewer light patterns, increasing speed
  • Can run 40GB or 100GB to 100m using MPO connector
  • Applications – larger private network


  • Color – Aqua
  • Core size – 50um
  • Data Rate – 10GB @ 850nm
  • Distance – up to 550 meters
  • Runs from 100GB to 150m using MPO connector
  • Applications – High speed networks, data centers, financial centers and corporate campuses


  • Color – Lime green
  • Fully compatible, can be mated with OM3 and OM4 wiring
  • Take advantage of a wider wavelength range between 850nm and 953nm
  • Designed to support short wavelength division multiplexing (SWDM)
  • Can transmit 40 Gb/s and 100 Gb/s
  • Applications – High-speed networks and data centers that require longer link distances and higher speeds.

4.4 Application

  • OM1 and OM2 have been widely deployed in buildings for many years, supporting Ethernet transmission with a maximum value of 1Gb;
  • OM3 and OM4 optical cables are usually used in the wiring environment of the data center, supporting the transmission of 10G or even 40/100G high-speed Ethernet.

4.5 When to use OM3 fiber patch cords?
OM3 fiber is an optical fiber designed to work with VCSELs. It conforms to the OM-3 fiber specification of ISO/IEC11801-2nd and meets the needs of 10 Gigabit Ethernet applications. There are many types of OM3 optical fibers, including indoor type, indoor/outdoor versatility, etc. The number of cores of the optical fiber ranges from 4 cores to 48 cores. All legacy multimode 50/125 fiber based applications are also supported, including support for LED light sources and laser light sources.

  • The transmission distance of Gigabit Ethernet using OM3 fiber system can be extended to 900 meters, which means that users do not need to use expensive laser devices when the distance between buildings exceeds 550 meters.
  • Within a distance of 2000 meters, standard 62.5/125μm multimode fiber can be used in various situations within the OC-12 (622Mb/s) rate range, and single-mode fiber will be used outside of this. However, the emergence of OM3 multimode fiber has changed this situation. Since OM3 fiber can increase the transmission distance of Gigabit and 10 Gigabit systems, the use of 850nm wavelength optical modules and VCSELs will be the most cost-effective wiring solution.
  • 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 at 1310nm wavelength in a gigabit system and 10 kilometers in a 10-gigabit system.
  • When the link length is less than or equal to 1000 meters, OM3 50μm multimode fiber can be used in the gigabit system, and single-mode fiber should be used in the 10G system.
  • When the link length is less than 300 meters, OM3 multimode fiber can be used in any Gigabit and 10 Gigabit systems.

4.6 When to use OM4 fiber patch cords?
For a typical link, the cost of optical modules is very expensive. Although the cost of single-mode fiber is cheaper than that of multi-mode fiber, the use of single-mode fiber requires very expensive 1300nm optical modules, and its cost is about 2-3 times that of 850nm multi-mode optical modules. The cost of the system is much lower than that of single-mode fiber systems.

When investing in fiber optic cabling, if you can consider increasing the initial investment in cabling and using better multi-mode fiber, such as OM4 fiber, you can ensure that the current multi-mode fiber technology is fully utilized and the overall cost of the current system is reduced; When you need to upgrade to higher speed systems, such as 40G and 100G, OM4 can still be used and will be more cost-effective.

In short, when the transmission rate is greater than 1Gb/s, the use of multimode fiber is a good system choice. When the system requires higher transmission rates, the following are our guidelines for selecting OM4 fiber:

  • For Ethernet users, in 10Gb/s system transmission, the transmission distance can reach 300m to 600m; in 40Gb/s and 100Gb/s systems, the transmission distance is 100m to 125m.
  • 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.

4.7 OM4 vs OM5: What’s the Difference?
Since OM1 and OM2 fibers cannot support data transmission speeds of 25Gbps and 40Gbps, OM3 and OM4 are the main choices for multimode fibers that support 25G, 40G, and 100G Ethernet. However, as bandwidth demands increase, so does the cost of fiber optic cables to support the migration to next-generation Ethernet speeds. In this situation, OM5 fiber was born to expand the advantages of multimode fiber in data centers.

The key difference between them is that at 4700 MHz-km, the EMB of OM4 fiber is only specified at 850 nm, while the OM5 EMB values ​​are specified at 850 nm and 953 nm, with a larger value at 850 nm than OM4. Therefore, OM5 fiber provides users with longer distances and more fiber options. Additionally, TIA has designated lime green as the official cable jacket color for OM5, while OM4 is the overwater jacket. OM4 is designed for 10Gb/s, 40Gb/s and 100Gb/s transfers, but OM5 is designed for 40Gb/s and 100Gb/s transfers, reducing the number of fibers for high-speed transfers.

Additionally, the OM5 cable can support four SWDM channels, each carrying 25G data, providing 100G Ethernet using a pair of multimode fibers. Additionally, it is fully compatible with OM3 and OM4 fibers. OM5 can be used worldwide for installations in a variety of enterprise environments, from campuses to buildings to data centers. In conclusion, OM5 fiber is better than OM4 in terms of transmission distance, speed and cost.

4.8 Summary of OM-type cables (Multimode mode fiber)
The multimode fiber technology has developed from OM1 multimode to OM5 which supports 40/100Gbps, which will enable users to get the most effective return on investment and become the best choice for backbone cabling or fiber to the desktop.

OM fiber cable

5. Summary of OS1, OS2, & OM1, OM2, OM3, OM4, and OM5 fiber optic cables
Single-mode optical fiber transmission has the advantages of long-distance, low attenuation, and large bandwidth. If the distance is greater than 2 kilometers, it is better to use single-mode optical cable; and within 2 kilometers, it is generally to use multi-mode optical cable. The cost-effective multi-mode optical cable system is more favored by customers during transmission.

Bonelinks can provide a variety of optical cables, including OS1 and OS2 single-mode fibers, and OM1, OM2, OM3, OM4, and OM5 multi-mode fibers, all of which can meet the wiring needs of different data centers. Contact us if you need it.

Echo Huang

Echo Huang is an expert wordsmith and marketing professional at Bonelinks with more than 8 years of experience in high technology businesses – fiber optics, IoT, and telecommunication. She is very glad to share industry knowledge and communicate with others.

More To Explore

Optical Transceiver

What Is An Eye Diagram?

Eye diagram, which is formed by overlapping the waveforms of each code element obtained from the scan due to the afterglow of the oscilloscope. It contains a wealth of information,

Read More »
Scroll to Top
Contact us