How to Realize the Conversion from Multimode Fiber to Single Mode Fiber?

Optical fiber is mainly used for data transmission because of its high transmission rate and large transmission capacity. Due to the strong anti-electromagnetic interference ability and small dispersion and loss of optical fiber, its transmission bandwidth is longer than that of network cables. However, whether to use multi-mode optical fiber or single-mode optical fiber for transmission depends on the actual network communication requirements. Distance is one of the important factors considered in fiber optic networking. Usually, the deployment of fiber optic networks involves the conversion of fiber transmission modes, especially the conversion from multimode fiber modules to single-mode fiber. Next, this article will introduce three conversion methods from multimode fiber to single-mode fiber.

1. When is it necessary to convert the multimode fiber module to single mode?

Before understanding the conversion method from multimode fiber to single-mode fiber, we must first figure out the difference between single-mode fiber and multimode fiber. Since single-mode fiber and multimode fiber support different transmission modes of light, their application ranges are also different. Single-mode fiber is primarily used for long-distance, high-bandwidth applications, while multimode fiber modules are primarily used for short-distance applications. However, fiber optic networks do not simply use one type of fiber, and fiber transmission mode conversion often occurs during signal transmission, such as multimode fiber to single-mode fiber mode conversion. When the network distance exceeds the maximum transmission distance of multimode fiber, it is usually necessary to perform mode conversion between multimode fiber and single-mode fiber. The conversion from multi-mode to single-mode depends on the deployed network devices and connection types. For example, low-cost legacy devices use multimode ports to connect to single-mode devices or multimode devices in buildings require single-mode connections to service providers.

2. The method of realizing the conversion from multi-mode optical fiber module to single-mode optical fiber

Since mode conversion in fiber optic networks is common, here are three methods that can achieve multimode fiber to single-mode fiber conversion.

(1) Fiber optic transceiver

As we all know, fiber optic transceivers support multi-mode fiber to single-mode fiber, dual-fiber to single-fiber, and wavelength conversion. Here we mainly explain the conversion from multimode fiber to single-mode fiber. Fiber optic transceivers can cost-effectively convert multimode fiber into single-mode fiber for transmission distances up to 140 kilometers, for example, SFP Gigabit Ethernet fiber optic transceivers can convert multimode fiber into single-mode fiber for Gigabit Ethernet single-mode fiber. In the practical application of extending the transmission distance of the fiber optic network, the fiber optic transceiver realizes the long-distance connection between two Ethernet switches by converting multimode fiber into single mode fiber.

(2) WDM transponder

WDM transponders also have the ability to convert multimode fiber to single-mode fiber similar to fiber optic transceivers. As the name suggests, WDM transponders are often used in WDM systems, especially DWDM systems, because in long-distance DWDM transmission, conversion from multimode fiber to single-mode fiber or single-mode fiber to multimode fiber is usually required.

(3) Mode adjustment fiber optic jumper

Compared with the above two methods, the mode-adjusted fiber patch cord is different in the conversion of multimode fiber module and single-mode fiber. The mode-adjusting fiber jumper cannot change the fiber type to extend the network transmission distance like a WDM transponder. It realizes the conversion from multi-mode fiber to single-mode fiber by changing the transmission mode of light. The fiber optic connector of the mode adjustment jumper can launch the single-mode laser to the center of the multimode fiber with a special displacement, so that the single-mode laser can propagate within the core diameter of the multimode fiber, thereby shielding when the light is in the multimode fiber The impact of differential mode delay effects when propagating in multiple modes. In addition, mode-adjusted fiber patch cords are only suitable for gigabit equipment applications.