Single mode vs Multi mode fiber-Difference between single mode and multi mode fiber

This section of fiber optics also covers following:
DWDM basics   •Fibre optic communication   •Types of WDM   •PDH Vs SDH   •SONET Vs SDH   •What is PDMA?   •What is WDM?  

This page on single mode vs multimode fiber describes difference between single mode and multi mode fiber systems.The other difference between terms are also provided. We will see the differences taking into consideration various comparison factors of transmission system such as data rate, distance, attenuation, time to travel and so on. The page also compares single mode and multimode fiber definitions, dimensions, types, applications, merits, demerits etc.


Single mode fiber cable due to small diametric core of 8-10 microns diameter, allows one mode of light to propagate through it. Multimode fiber cable due to large diametric core of about 62.5 microns diameter, allows multiple simultaneous mode of light to propagate through it.

Dimensions of single mode/multimode fiber

fiber optic cable with core and cladding

In single mode optic fiber cable, core-to-cladding diameter is about 9 microns by 125 microns. In multi mode optic fiber cable, core-to-cladding diameter is about 50 (or 62.5) microns by 125 microns. The figure depicts the fiber optic cable and mentions the core and cladding portions.

Transmission distance and rate

Multimode optic fiber permits the signal transmission up to the distance of about 10miles. Multimode fibers use cheaper optical transmitters/receivers. Single mode fiber covers distance greater than 10miles. It uses costly laser diode as optical transmitters. Transmission rate of single mode fiber is higher than the multimode fiber. It is also about 2 to 4 times costlier compare to multimode version.

Attenuation/Time to travel

In a single mode fiber due to single core, the light reflections will be less and hence attenuation is lower which makes light signal to reach faster. In a multimode fiber due to multiple cores, the light reflections will be more and hence attenuation is higher which makes light signal to reach slower on the other end. But it can carry more data due to simultaneous transmissions.

Merits, De-merits

As mentioned each has their own merits and demerits based on target application. The major demerit of multimode fiber optical cable is that broadband RF signals cannot be propagated through it.


Single mode fiber is used for long distance communication and for carrying very high bandwidth signal. The major applications of single mode are CATV, Telcos, universities as well as colleges. Laser diode is used as optical transmission system equipment here. Multimode fiber is used for short distance communication mainly for video/audio/data based Wireless LAN applications. LED based fiber optic equipment is used for this.


There are two major types of multimode fiber viz. Step-Index and Graded-Index Multimode Fiber.
Refer Single Mode Step Index Vs Multimode Graded Index Fiber➤➤.

Comparison between Single Mode Fiber and Multimode Fiber

Following table mentions key comparison factors between single mode fiber and multimode fiber:

Specification Single mode fiber multimode fiber
Cost of fiber Less Expensive Expensive
Transmission Equipment More Expensive (laser diode) Basic and Low Cost (LED)
Attenuation Low High
Transmission wavelengths 1260 nm to 1640 nm 850 nm to 1300 nm
Application of Use connections are more complex Larger core, easier to handle
Distance Access/medium/long haul networks (> 200 Km) ocal networks (< 2 Km)
Bandwidth Nearly infinite bandwidth (> 1 Tb/s for DWDM) Limited Bandwidth (10 Gb/s over short distances)
Advantages/disadvantages Provides higher performance, but building the network is expensive. The fiber is more costly, but the network deployment is relatively inexpensive.

What is Difference between

After studying difference between single mode and multi mode fiber one can also study comparison between PDH vs SDH, SONET vs SDH etc.
SONET versus SDH
difference between FDM and OFDM
Difference between SC-FDMA and OFDM
Difference between TDD and FDD
Difference between 802.11 standards viz.11-a,11-b,11-g and 11-n

Optical Fiber related links

DWDM system basics   Fibre optic communication   Types of WDM   PDH versus SDH   SONET versus SDH   What is PDMA?   What is WDM?  

RF and Wireless Terminologies