Single Mode vs. Multi Mode | Product Knockout

Product_Knockout“Our Product Knock-out series is a match-up between two similar products. In boxing terms, think same weight class, same caliber, and same level of experience and amount of exposure. The purpose of these posts are for you to see a side-by-side view of two similar products, and to be able to understand which one will be crowned champ for your specific purposes. Take your seats and prepare for battle, because the gloves are coming out.”

Before this post gets into the compare and contrast of single-mode and multi-mode, it’s important to know what a mode is. To put it simply, a mode is the path that a light beam travels down the fiber. Single-mode and multi-mode both feature a core that allows light to travel down the center of the fiber and carry signals. However, the differences outweigh the similarities, so let’s take a closer look at the differences in these two kinds of cables.

What is Single-Mode Fiber?

Single-mode fiber optic cable is the simplest type of optical fiber. Signals that are in a single-mode fiber travel straight down the center of the core without bouncing off the edges. This type of mode is also very small with a very thin core. The core of a single-mode fiber optic cable is 5-10 microns in diameter which translates to millionths of a meter. Single-mode fiber optic cable is wrapped together in a large bundle and used in telephone signals, cable TV and internet applications. The signal from a single-mode fiber optic cable can travel over 100 km (60 miles). In single-mode fiber optic cable the MFD (mode field diameter) is large and easy to splice/connect. This also makes it sensitive to microbends. Microbends describe the source of signal loss or attenuation in fiber optic cable. 

What is Multi-Mode Fiber?

Multi-mode fiber is a more complex type of optical fiber. These fibers are larger than single-mode fibers at roughly ten times the diameter.  This size allows light beams to travel through the core by a variety of different paths/modes.  These paths can be straight through the core, or the light can be bounced off the edges. Multi-mode cables are used in applications where short distances are used, such as linking computer networks.

Single-Mode vs. Multi-Mode Fiber

When comparing single-mode and multi-mode fiber, the only real similarity between them is that they are both ways to send fiber optic signals.


Single-mode vs. Multi-mode

Single-mode is smaller and used in applications where a signal needs to be sent great distances. In contrast, multi-mode is used in applications where short distances are being used. Single-mode only allows one signal to be sent straight down the core of the fiber, where multi-mode allows multiple signals to be sent and bounced off the edges of the core. In single mode fiber optic cable the MFD (mode field diameter) is larger than in multi-mode due to the core sizes. In single-mode the core is smaller, so the MFD is larger, where in multi-mode the core is larger which means the MFD is smaller. 

Winner by unanimous vote? Instead, it seems as if the match has ended in a technical decision.
In this case it looks like our crowned champ depends on your specific application use.
If you’re unsure about what cable or what mode you’ll need in order to meet the needs of your application, consult with one of Allied’s knowledgeable sales reps by submitting an RFQ.
Visit our website to learn more about fiber optic cable and all of our Prysmian/Draka Group products.

About awcwire
Allied Wire & Cable is a value-added manufacturer and distributor of electrical wire and cable, tubing, and more. We are a family owned and operated company, serving a wide range of industries, including the military, automotive, aerospace, and telecommunications markets. Allied is headquartered in Collegeville, PA. Additional locations can be found across the US, in Phoenix, AZ; Bedford, NH; Pewaukee, WI; Rochester, NY, Tampa, FL; and Mt. Juliet, TN. For more information on Allied, visit our main website at

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