How to Realize Multimode to Single-Mode Fiber Conversion?

Fiber optics are mainly used for data transmission due to their efficiency and high capacity. Multimode fiber (MMF) and single-mode fiber (SMF) are fiber optic cables categorized based on their transmission modes. One key distinction between them is the transmission distance they can support. Fiber mode conversion is required when the distance is an important parameter to consider in optical applications. In this tutorial, three methods will be introduced to support mode conversion from multimode to single-mode fibers.

When Is Multimode to Single-Mode Conversion Required?

• There is a need for connectivity between multimode equipment within a building and a single-mode network outside.

• Legacy equipment utilizes LC and SC ports with fixed multimode fiber, but there is a requirement for connectivity to single-mode equipment.

• The proprietary Single-mode SFPs are expensive, resulting in high costs.

• The objective is to connect multimode network equipment to a single-mode CWDM multiplexer.

How to Realize Multimode to Single-Mode Fiber Conversion?

Since mode conversion in the optical network is universal, here are three methods that can convert multimode to single-mode.

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

A multimode to single mode converter can extend a MM network across SM fiber with distances up to 160km in a cost-effective way. For example, a 550m/20km 850nm/1310nm SFP Gigabit Ethernet MMF to SMF converter can support mode conversion from multimode fiber (up to 550 m) to single-mode fiber (up to 20 km) for Gigabit Ethernet (1000 Mbps).

In the application of extending fiber network distances, two Ethernet switches equipped with multimode fiber ports are connected utilizing a pair of multimode to single mode converters that convert the multimode fiber to single-mode fiber and enable network connectivity across the distance between the switches, as shown in the picture below. To explore further, take a look at the article What Is Media Converter and How to Choose It?

WDM Transponder for MMF-to-SMF Fiber Conversion

Similar to multimode to single mode fiber converter, WDM transponder also can convert multimode to single-mode fiber. As its name shows, transponder is often used in WDM systems, especially in DWDM systems. Because in the long run DWDM transmission, MMF to SMF or SMF to MMF conversions are usually needed.

In the given example, the WDM transponder features two ports, with one equipped with a single-mode SFP and the other with a multi-mode SFP. An OM3 MMF is used to connect the multi-mode port of the WDM transponder to the multi-mode port of the switch. To extend the reach between buildings, the WDM transponder's SMF SFP ports are connected using a single-mode OS2 fiber.

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

Compared with the two methods mentioned above, mode conditioning fiber cable is different in the conversion between multimode and single-mode fiber. Not able to convert signals into electrical ones as WDM transponder, mode conditioning patch cable launches the laser at a precise offset from the center of the multimode fiber. This causes the laser to spread across the diameter of the fiber core, reducing the effect known as differential mode delay (DMD) which occurs when the laser couples onto only a small number of available modes in multimode fiber. In addition, mode conditioning fiber cable is limited to be used in applications that use Gigabit 1000BASE-LX (or 10-Gigabit Ethernet 10GBASE-LRM and 10GBASE-LX4) equipment.

Conclusion

FS.com offers a wide range options of MMF-to-SMF conversion for Fast Ethernet and Gigabit Ethernet. In addition, we offer matching SFP transceiver modules and high-quality fiber patch cables, which help you deploy the network most cost-effectively. For more information, please visit our online platform. By registering online, you can easily browse our product catalog and conveniently place orders. Register now and experience a seamless online shopping experience!