The main difference between single mode fiber (SMF) and multimode fiber is the size of the core. Single mode fiber has a much smaller core, typically around 9 microns in diameter, which allows for a single mode of light to travel down the fiber. This results in a higher bandwidth and longer transmission distances, making it ideal for long-haul communication.

On the other hand, multimode fiber has a larger core, typically around 50 or 62.5 microns in diameter, which allows for multiple modes of light to travel down the fiber. This results in a lower bandwidth and shorter transmission distances, making it more suitable for short-distance communication within buildings or campuses.

In summary, the main difference between SMF and multimode fiber is the size of the core, which affects the bandwidth and transmission distances of the fiber.

Single Mode vs Multimode Fiber Distance

It’s known that single mode fiber is suitable for long-distance applications, while multimode optical fiber is designed for short-distance runs. Then when it comes to single mode vs multimode fiber distance, what’s the quantifiable differences?

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.