Optical Fiber TOPICS

Differences among Multimode (OM1, OM2, OM3, OM4, OM5) and Single Mode (OS1, OS2) Fiber


What are OM and OS type fiber optic cables?
In ANSI/TIA-568.3-D, the TIA adopted the nomenclature for fiber found in the international standard ISO/IEC 11801. The multimode fiber is prefixed with “OM” and the singlemode mode “OS”.

The new designation in ANSI/TIA-568.3-D should alleviate some of the confusion associated with application support distance issues. Each “OM” has a minimum Modal Bandwidth (MBW) requirement.


Bandwidth and attenuation comparison between different OM fiber optic cables

Multimode FiberOverfilled launch bandwidth (MHz.km)Laser LaunchAttenuations (dB/km)
Fiber TypeTIA Fiber StandardCore diameter (um)850 nm1300 nm850 nm850nm1300nm
OM1492-AAAA62.5200500Not specified3.51.5
OM2492-AAAB50500500Not specified3.51.5

Attenuation refered to YOFC Multimode Fiber.


Maximum channel length comparison between different OM fiber optic cables

OM1up to 2000m275m550m33mup to 300mNot specifiedNot specified
OM2up to 2000m550m550m82mup to 300mNot specifiedNot specified
OM3up to 2000m550m550m300mup to 300m100m100m
OM4up to 2000m1000m550m550m400m*150m150m
OM5up to 2000mNot specifiedNot specifiedNot specified400m*150m150m


Attenuation comparison between different OS fiber optic cables

1310 nm1383nm1550 nm
OS1(EN50173-1:Ed.2: 2010)1.0 dB/km1.0 dB/km1.0 dB/km
OS2(EN50173-1:Ed.2: 2010)0.4 dB/km0.4 dB/km0.4 dB/km
OS1(ISO/IEC11801Ed.2.2:2010)1.0 dB/kmNot specified1.0 dB/km
OS2(ISO/IEC11801Ed.2.2: 2010)0.4 dB/km0.4 dB/km0.4 dB/km
OS2(ISO/IEC24702: 2006)0.4 dB/km0.4 dB/km0.4 dB/km