What is OM4 Fiber?

February 11, 2011
By Colin Yao

:: What Is OM4 Fiber Anyway?

OM4 fiber is a laser-optimized, high bandwidth 50um multimode fiber. OM4 fiber is not a new fiber type. All major fiber manufacturers have been selling a fiber with an effective modal bandwidth (EMB) value equivalent to that specified by OM4 since 2005. The change is that there is now a standard that is specifically targeted at this product. Prior to the standardization of OM4, these higher bandwidth fibers were sold as a part of OM3.

OM3 and OM4 fiber are referred to as “laser-optimized” multimode fibers because they are specifically designed for optimum performance when used with low cost Vertical-Cavity-Surface-Emitting-Lasers (VCSELs).

OM4 fiber is designed to enhance the system cost benefits enabled by 850nm VCSELs for existing 1 Gb/s and 10 Gb/s applications as well as future 40 Gb/s and 100 Gb/s systems.

OM4 fiber supports Ethernet, Fibre Channel, and OIF applications, allowing extended reach upwards of 550 meters at 10 Gb/s for ultra long building backbones and medium length campus backbones.

:: Why Is It Called OM4?

Multimode fibers are identified by the OM (“optical mode”) designation as outlined in the ISO/IEC 11801 standard.

  • OM1, for fiber with 200/500 MHz*km overfilled launch (OFL) bandwidth at 850/1300nm (typically 62.5/125um fiber)
  • OM2, for fiber with 500/500 MHz*km OFL bandwidth at 850/1300nm (typically 50/125um fiber)
  • OM3, for laser-optimized 50um fiber having 2000 MHz*km effective modal bandwidth (EMB, also known as laser bandwidth), designed for 10 Gb/s transmission.
  • OM4, for laser-optimized 50um fiber having 4700 MHz*km EMB bandwidth designed for 10 Gb/s, 40 Gb/s, and 100 Gb/s transmission.

:: OM4 Fiber Standard

The TIA/EIA approved OM4 specification in its TIA-492AAAD in 2009. IEC’s document covering OM4 standard is IEC 60793-2-10 as fiber type A1a.3.

:: Bandwidth Comparison of OM1, OM2, OM3, and OM4 Fibers

The following table shows the bandwidth comparison among OM1, OM2, OM3 and OM4 fibers.

Multimode Fiber
Bandwidth (MHz * km)
OM Designation
TIA Fiber Standard

Fiber Type
(um)

Overfilled Launch (OFL)
@850nm
Effective Modal Bandwidth (EMB)
@850nm
Overfilled Launch (OFL)
@1300nm
OM1
492-AAAA
62.5/125
200
n/s
500
OM2
492-AAAB
50/125
500
n/s
500
OM3
492-AAAC
50/125
1500
2000
500
OM4
492-AAAD
50/125
3500
4700
500

The following table and graph shows the maximum distance different multimode fibers can carry.

Applications
Wavelength(nm)
Maximum Channel Length (meters)
OM1
OM2
OM3
OM4
Fibre Channel
4 Gb/s
850
70
150
380
400
8 Gb/s
850
21
50
150
200
16 Gb/s
850
15
35
100
130
 
Ethernet
1 Gb/s
850
275
550
800
1100
10 Gb/s
850
33
82
300
550
40 & 100 Gb/s
850
n/s
n/s
100
125
1 Gb/s
1300
550
550
550
550
10 Gb/s
1300

220
(10GBase-LRM)
300
(10Gbase-LX4)

220
(10GBase-LRM)
300
(10Gbase-LX4)

220
(10GBase-LRM)
300
(10Gbase-LX4)

220
(10GBase-LRM)
300
(10Gbase-LX4)

 

:: OM4 Fiber Optic Cable Assemblies Available from Fiber Optics For Sale Co.

Fiber Optics For Sale Co. offers factory direct OM4 Fiber – Standard and custom OM4 Fiber Optic Assemblies, built to specs OM4 fiber assemblies, OM4 fibre channel cables for quality installations.

The following list shows the OM4 cable assembly products we carry.

  • OM4 Clear Curve Multimode Fiber Optic Assemblies
  • OM4 Infinicor eSX Multimode Fiber Optic Assemblies
  • OM4 Fibre Channel Cables, Standard and Custom Fibre Channel cable Assemblies
  • Other OM4 Fiber Assemblies, Custom OM4 Fiber, Built to Specs OM4 Fiber Assemblies