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MULTIMODE VS SINGLEMODE


The most basic distinction in Fiber is Multimode vs Singlemode, Below the list:

DistinctionMultimodeSinglemode
DistanceShort Distance ; < 500mLong Distance ; Up to 120KM
Transmission Band / Wavelength First window ; 850nmSecond Window (O Band) ; 1310nm
Third Window (C Band) ; 1550nm
Fourth Window (L Band) ; 1570-1610nm
Core SizeBigger ; 50/62.5 µSmaller ; 8 - 10 µ
CostCheaper for the transceiver
More expensive for the cable
More expensive for the transceiver
Cheaper for the cable
Cable TypesOM1 and OM2 OM1/OM2 aka FDDI, found with orange fiber jacket. Only for low bandwidth, start fails at 10G speed.

OM3 and OM4 OM3/OM4 aka laser optimized, found with magenta or aqua fiber jacket. Use for high bandwidth 10G, 40G and 100G
Actually singlemode only have 1 type of the cable but it comes in many different formulation ;
- LWPF (Low Water Peak Fiber)
- DSF (Dispersion Shifted Fiber)
- NZDSF (Non Zero Dispersion Shifted Fiber)
- Band Insensitive Fiber
- etc

Frequently Asked Question about Single Mode vs Multimode Fiber

Q: What is better single mode or multimode fiber?
As has 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?
This answer for this question is “no”. Multimode fiber and single mode fiber have different core size, and the numbers of light mode that they transmit is also different. If you mix the two fibers, or connect them together directly, you’ll lose 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 multimode transceiver on single mode fiber?
Generally speaking, the answer is “no”. Large optical loss will occur if 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 converter also can be used to solve such problems between single mode transceiver and multimode transceiver.

Q: Single mode vs multimode Fiber: which should I choose?
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 is enough for the distance of 300-400 meters. While in applications that require distance up to several thousands of meters, the singlemode fiber is the best choice. And in applications which can use single mode and multimode fiber, other factors like cost and future upgrade requirements should be taken into consideration for your choice.