How to convert from multimode to singlemode?

Optical modules can be divided into single-mode optical modules and multi-mode optical modules according to fiber type. Different fiber types have different characteristics such as fiber core and transmission distance. This article will analyze in detail the different properties of single-mode and multi-mode optical fibers, and how to achieve conversion between single-mode and multi-mode optical fibers. If you need to learn about or purchase single-mode and multi-mode fiber optic converters, please feel free to contact us.

Multimode Fiber vs Single-mode fiber 

Multimode Fiber (MMF)

The core diameter of multimode fiber is 50μm or 62.5μm, and the diameter of the cladding is 125μm. Due to the large core diameter of optical fiber, light has multiple transmission modes in it. Compared with SMF, the transmission bandwidth is mainly dominated by modal dispersion.

Single-mode Fiber (SMF)

The diameter of the single-mode optical fiber core is 8μm~10μm, and 9μm is commonly used. The core is surrounded by a glass envelope with a lower refractive index than the core, commonly known as the cladding. The diameter of the cladding is 125 μm. The cladding keeps the light within the core. On the outside is a thin plastic jacket, the coating, to protect the cladding. Since the core of the optical fiber is very thin and the refractive index is distributed in a step-like manner, light forms a single-mode transmission in the optical fiber.

Fiber Mode Conversion Considerations

Fiber type

Optical fiber types are mainly divided into single-mode optical fiber and multi-mode optical fiber. They have different core diameters and transmission modes, and the transmission distances are also different. Therefore, you should consider the fiber characteristics and equipment compatibility when choosing.

Connector type

Commonly used fiber optic interface types are: LC, SC, FC, ST, MPO. The fiber optic interfaces are distributed at both ends of the fiber optic cable to connect different devices. Therefore, when choosing optical fiber, you must consider the equipment connected at both ends of the optical fiber and the compatibility of the optical fiber interface and the device port.

Wavelength

Common wavelengths of single-mode fiber are 1310nm, 1550nm and wdm. Common wavelengths for multimode fiber are 850nm or 1310nm. Therefore, when selecting fiber types, you also need to consider the characteristics of different wavelengths and the compatibility of different wavelengths with various devices.

Cost

Single-mode fiber uses a large amount and the unit price is cheaper; multi-mode fiber has a gradient core refractive index and a more complicated production process, so the unit price is more expensive than single-mode fiber. However, because they are used for short-distance transmission, the unit price is smaller, so The total cost of use is generally lower than single-mode fiber.

Standards and Regulatory compliance

Single-mode optical fiber can be divided into the following types according to the recommended specifications of the International Telecommunications Union ITU-T:

• G.652: Dispersion non-shifted single-mode fiber, zero-dispersion wavelength in the 1.3μm window, suitable for long-distance transmission, low loss (0.3dB/km~0.4dB/km), good performance at both 1310nm and 1550nm wavelengths .
• G.653: Dispersion-shifted optical fiber, the zero-dispersion wavelength is moved to 1550nm. It is suitable for large-capacity and long-distance transmission, but there are problems with nonlinear effects.
• G.654: Cutoff wavelength shifted fiber, suitable for deep sea and special environments, cutoff wavelength shifted to reduce bending loss.
• G.655: Non-zero dispersion shifted optical fiber, suitable for long-distance, large-capacity transmission, solving the nonlinear effect problem of G.653.
• G.656: Low slope non-zero dispersion shifted fiber, suitable for applications requiring low slope dispersion characteristics.
• G.657: Bending-resistant optical fiber, suitable for dense wiring environments, with good bending resistance.

According to the ISO 11801 standard, multimode optical cables can be divided into OM1, OM2, OM3, OM4 and OM5 optical fibers.

OM1 optical fiber

OM1 fiber typically has an orange jacket and has a core size of 62.5 µm. It can support 10 Gigabit Ethernet up to 33 meters, and it is most commonly used in 100 Mbit Ethernet applications. This type usually uses an LED light source.

OM2 optical fiber

Similarly, OM2 fiber also has an orange jacket and uses an LED light source, but has a smaller core size of only 50 µm. It supports up to 10 Gigabit Ethernet up to 82 meters in length, but is more commonly used in 1 Gigabit Ethernet applications. .

OM3 optical fiber

OM3 fiber has a light green jacket and has the same 50 µm core size as OM2, but the cable is optimized for laser-based devices and OM3 supports 10 Gigabit Ethernet up to 300 meters.

In addition, OM3 is capable of supporting 40 Gigabit and 100 Gigabit Ethernet up to 100 meters long, but 10 Gigabit Ethernet is most commonly used.

OM4 optical fiber

OM4 fiber is fully backwards compatible with OM3 fiber and shares the same unique light green jacket. OM4 is specifically developed for VSCEL laser transmission, allowing 10 Gig/s link distances up to 550m compared to OM3’s 300M. It Able to run 40/100GB up to 150 meters using MPO connector.

OM5 optical fiber

OM5 fiber, also known as WBMMF (Wideband Multimode Fiber), is the latest multimode fiber and is backward compatible with OM4. Its core size is the same as OM2, OM3 and OM4. The color of the OM5 fiber jacket is lime green. It is designed and specified to support at least four WDM channels through the 850-953 nm window at a minimum speed of 28Gbps per channel.

When Is Multimode to Single-Mode Conversion Required?

Multi-mode optical fiber is generally used in the internal network of data centers and internal optical networks of campuses/enterprises/buildings. When these local area networks with higher transmission rate requirements need to establish long-distance transmission with external networks, multi-mode optical fiber is used to convert to single-mode optical fiber. mode fiber technology to achieve better transmission effects

How to Realize Multimode to Single-Mode Fiber Conversion?

There are usually three options for conversion between multimode and single-mode optical fibers. These three options are explained below.

Fiber to Fiber Media Converter for MMF-to-SMF Fiber Conversion

Fiber to Fiber Media Converter is a simple O-E-O device that converts single-mode/multi-mode optical fiber signals into electrical signals through a single-mode/multi-mode module, and then converts them into electrical signals through another multi-mode/single-mode module. Multimode/single-mode optical signals continue to be transmitted. Fiber to Fiber Media Converter has a simple structure, plug-and-play, and can be flexibly applied to any application scenario that requires MMF/SMF transfer.

WDM Transponder for MMF-to-SMF Fiber Conversion

WDM Transponder is another switching solution, similar to Fiber to Fiber Media Converter. WDM Transponder is a device used in WDM transmission systems. It can support the simultaneous use of dozens of optical modules and is suitable for multiple application scenarios that require MMF/SMF transfer.

Mode Conditioning Fiber Cable for MMF-to-SMF Fiber Conversion

Due to the different core diameters and propagation modes of single-mode fiber and multi-mode fiber, SMF and MMF generally cannot be directly connected. Mode conditioning of light can be achieved by using Mode Conditioning Fiber Cable. Mode Conditioning Fiber Cable has a large loss in mode conversion, and the dispersion of multi-mode optical fiber is large, so it is only suitable for low-speed, short-distance communication applications.

SULITON Fiber Mode Conversion Solutions

Conclusion

In short, the need to convert from multimode fiber to single-mode fiber is not common. There are three specific solutions. The most commonly used one is Fiber to Fiber Media Converter, and SULITON also has corresponding products. If you have relevant needs, please feel free to contact us

FAQ

Single mode to Multimode converter price？