Singel-mode VS Multi-mode Fiber Optic Cable Types
December ,22 ,2025
Single mode fiber (SMF) and multimode fiber (MMF) are both widely used across various applications, but their differences still confuse many. This article takes an in-depth look at key factors，including basic structure, transmission distance, types，to clearly compare these two fiber types.
Single mode fiber optic cable consists of a very small glass core surrounded by cladding with a lower refractive index. The core diameter is typically about 9 microns, allowing only a single light mode to propagate. This minimizes modal dispersion, resulting in longer transmission distances and higher signal integrity.
Because of these characteristics, single mode fiber is widely used in long-haul and high-speed networks, such as telecommunications backbones, cable television systems, and metropolitan networks.
OS1 single mode fiber uses a 9-micron core and is mainly designed for indoor applications. It supports a single light path, reducing dispersion and enabling high-bandwidth transmission over long distances.
OS1 fiber has a maximum attenuation of 0.4 dB/km at 1310 nm and 0.3 dB/km at 1550 nm, with a bandwidth of 200 MHz·km at 1310 nm. It typically supports transmission distances of up to 10 km at 10 Gbps without additional amplification.
OS2 fiber also features a 9-micron core but is optimized for outdoor and long-distance deployment. It offers lower attenuation and improved performance compared to OS1.
OS2 cables have a maximum attenuation of 0.3 dB/km at both 1310 nm and 1550 nm, and a bandwidth of 500 MHz·km at 1310 nm. This allows transmission distances of up to 40 km at 10 Gbps without signal regeneration.
Multimode fiber optic cable has a larger core diameter, typically 50 or 62.5 microns, allowing multiple light modes to propagate simultaneously. While this results in higher modal dispersion and shorter transmission distances, multimode fiber is more cost-effective and easier to install.
It is commonly used in short-distance applications, such as local area networks (LANs), data centers, and campus networks.
OM1 fiber has a 62.5-micron core and supports transmission distances of up to 300 meters at 10 Gbps. It offers a bandwidth of 200 MHz·km at 850 nm and a maximum attenuation of 3.5 dB/km at 850 nm.
OM2 fiber uses a 50-micron core and supports distances of up to 550 meters at 10 Gbps. It provides a bandwidth of 500 MHz·km at 850 nm with a maximum attenuation of 3.0 dB/km.
OM3 fiber, also with a 50-micron core, is laser-optimized for higher speeds. It supports up to 1000 meters at 10 Gbps and 400 meters at 40 Gbps. Its bandwidth reaches 2000 MHz·km at 850 nm, with a maximum attenuation of 3.0 dB/km.
OM4 fiber extends performance further, supporting 550 meters at 40 Gbps and 150 meters at 100 Gbps. It offers a bandwidth of 4700 MHz·km at 850 nm, with attenuation limited to 3.0 dB/km.
OM5 fiber is designed for wideband multimode applications, enabling short-wave wavelength division multiplexing (SWDM). It supports up to 1000 meters at 40 Gbps and 150 meters at 100 Gbps, with the same 4700 MHz·km bandwidth at 850 nm and 3.0 dB/km attenuation.
A: As has been mentioned above, single mode fiber and multimode fiber cable have their own advantages on cost and applications. There is no such thing that single mode optical fibers are better than multimode ones. Just choosing the best-fit one for your applications is ok.
A: This answer for this question is “no”. Multimode fiber and single mode fiber have different core sizes, and the number of light modes that they transmit is also different. If you mix the two fibers, or connect them together directly, you’ll lose a large amount of optical loss, resulting in a link flapping or being down. Keep in mind that never mix different types of cabling randomly.
A: Generally speaking, the answer is "no". Large optical loss will occur if a multimode transceiver is connected with single mode fiber. However, the opposite will work. For example, 1000BASE-LX single mode SFP can work on multimode fiber cable by using mode conditioning fiber cable. Sometimes, fiber media converters also can be used to solve such problems between single mode transceivers and multimode transceivers.
A: When making a decision between single mode and multimode fiber cables, the first factor to consider is the fiber distance which you need actually. For example, in a data center, multimode fiber cables are enough for the distance of 300-400 meters. While in applications that require distance up to several thousands of meters, the single mode fiber is the best choice. And in applications that can use single mode and multimode fiber, other factors like cost and future upgrade requirements should be taken into consideration for your choice.
Single-Mode Fiber Optic Cable
Single mode fiber optic cable consists of a very small glass core surrounded by cladding with a lower refractive index. The core diameter is typically about 9 microns, allowing only a single light mode to propagate. This minimizes modal dispersion, resulting in longer transmission distances and higher signal integrity.
Because of these characteristics, single mode fiber is widely used in long-haul and high-speed networks, such as telecommunications backbones, cable television systems, and metropolitan networks.
OS1 Single-Mode Fiber Optic cable
OS1 single mode fiber uses a 9-micron core and is mainly designed for indoor applications. It supports a single light path, reducing dispersion and enabling high-bandwidth transmission over long distances.
OS1 fiber has a maximum attenuation of 0.4 dB/km at 1310 nm and 0.3 dB/km at 1550 nm, with a bandwidth of 200 MHz·km at 1310 nm. It typically supports transmission distances of up to 10 km at 10 Gbps without additional amplification.
OS2 Single-Mode Fiber Optic Cable
OS2 fiber also features a 9-micron core but is optimized for outdoor and long-distance deployment. It offers lower attenuation and improved performance compared to OS1.
OS2 cables have a maximum attenuation of 0.3 dB/km at both 1310 nm and 1550 nm, and a bandwidth of 500 MHz·km at 1310 nm. This allows transmission distances of up to 40 km at 10 Gbps without signal regeneration.
| TYPE | CORE DIAMETER | MAXIMUM ATTENUATION | OPERATING WAVELENGTH | DISTANCE | BANDWIDTH |
|---|---|---|---|---|---|
| OS1 | 9 microns | 0.4 dB/km |
1550nm at 0.3 dB/km 1310nm at 0.4 dB/km |
10km at 10 Gbps | 200 MHz·km |
| OS2 | 9 microns | 0.3 dB/km |
1550nm at 0.3 dB/km 1320nm at 0.3 dB/km |
40km at 10 Gbps | 500 MHz·km |
Multi-mode Fiber Optic Cable
Multimode fiber optic cable has a larger core diameter, typically 50 or 62.5 microns, allowing multiple light modes to propagate simultaneously. While this results in higher modal dispersion and shorter transmission distances, multimode fiber is more cost-effective and easier to install.
It is commonly used in short-distance applications, such as local area networks (LANs), data centers, and campus networks.
OM1 Multi-mode Fiber Optic Cable
OM1 fiber has a 62.5-micron core and supports transmission distances of up to 300 meters at 10 Gbps. It offers a bandwidth of 200 MHz·km at 850 nm and a maximum attenuation of 3.5 dB/km at 850 nm.
OM2 Multi-mode Fiber Optic Cable
OM2 fiber uses a 50-micron core and supports distances of up to 550 meters at 10 Gbps. It provides a bandwidth of 500 MHz·km at 850 nm with a maximum attenuation of 3.0 dB/km.
OM3 Multi-mode Fiber Optic Cable
OM3 fiber, also with a 50-micron core, is laser-optimized for higher speeds. It supports up to 1000 meters at 10 Gbps and 400 meters at 40 Gbps. Its bandwidth reaches 2000 MHz·km at 850 nm, with a maximum attenuation of 3.0 dB/km.
OM4 Multi-mode Fiber Optic Cable
OM4 fiber extends performance further, supporting 550 meters at 40 Gbps and 150 meters at 100 Gbps. It offers a bandwidth of 4700 MHz·km at 850 nm, with attenuation limited to 3.0 dB/km.
OM5 Multi-mode Fiber Optic Cable
OM5 fiber is designed for wideband multimode applications, enabling short-wave wavelength division multiplexing (SWDM). It supports up to 1000 meters at 40 Gbps and 150 meters at 100 Gbps, with the same 4700 MHz·km bandwidth at 850 nm and 3.0 dB/km attenuation.
| TYPE | CORE DIAMETER | MAXIMUM ATTENUATION | OPERATING WAVELENGTH | DISTANCE | BANDWIDTH |
|---|---|---|---|---|---|
| OM1 | 62.5 microns | 3.5 dB/km | 200 MHz·km at 850nm | 300m at 10 Gbps | 200 MHz·km |
| OM2 | 50 microns | 3.0 dB/km | 500 MHz·km at 850nm | 550m at 10 Gbps | 500 MHz·km |
| OM3 | 50 microns | 3.0 dB/km | 2000 MHz·km at 850nm |
1000m at 10 Gbps 400m at 40 Gbps |
2000 MHz·km |
| OM4 | 50 microns | 3.0 dB/km | 4700 MHz·km at 850nm |
550m at 40 Gbps 150m at 100 Gbps |
4700 MHz·km |
| OM5 | 50 microns | 3.0 dB/km | 4700 MHz·km at 850nm |
1000m at 40 Gbps 150m at 100 Gbps |
4700 MHz·km |
Frequently Asked Question about Single Mode vs Multimode Fiber Optic Cable
Q: What is better single mode or multimode fiber type?
A: As has been mentioned above, single mode fiber and multimode fiber cable have their own advantages on cost and applications. There is no such thing that single mode optical fibers are better than multimode ones. Just choosing the best-fit one for your applications is ok.
Q: Can I mix single mode and multimode fiber type?
A: This answer for this question is “no”. Multimode fiber and single mode fiber have different core sizes, and the number of light modes that they transmit is also different. If you mix the two fibers, or connect them together directly, you’ll lose a large amount of optical loss, resulting in a link flapping or being down. Keep in mind that never mix different types of cabling randomly.
Q: Can I use a multimode transceiver on single mode fiber optic cable?
A: Generally speaking, the answer is "no". Large optical loss will occur if a multimode transceiver is connected with single mode fiber. However, the opposite will work. For example, 1000BASE-LX single mode SFP can work on multimode fiber cable by using mode conditioning fiber cable. Sometimes, fiber media converters also can be used to solve such problems between single mode transceivers and multimode transceivers.
Q: Single mode vs multimode fiber optic cable type: which should I choose?
A: When making a decision between single mode and multimode fiber cables, the first factor to consider is the fiber distance which you need actually. For example, in a data center, multimode fiber cables are enough for the distance of 300-400 meters. While in applications that require distance up to several thousands of meters, the single mode fiber is the best choice. And in applications that can use single mode and multimode fiber, other factors like cost and future upgrade requirements should be taken into consideration for your choice.