Standard grade multimode fiber with OM (optical multi-mode) to represent a different bandwidth and the maximum distance at different transmission levels.
Introduced species
01 OM2 Fiber
OM2 fiber was born in 1988, it is 50/125 mm graded index multimode fiber. And that from the standard design are based on the way the light emitting diode LED, low bandwidth requirements, with the LED for 100Mbit / s and a lower transmission rate.
Core diameter and numerical aperture are relatively small, effectively reducing mode dispersion in multimode fiber, significant increase in bandwidth, the production costs are reduced 1/3. 
02 OM3 Fiber
With 850nm vertical emitting laser VCSEL (Vertical Cavity Surface Emitting Laser) commercial, its fast becoming a major source of multimode communication system. VCSEL laser spot size of about 30um, having good stability, long life, and low price has advantages. 
In order to improve 850nm VCSEL laser based multimode optical fiber transmission system capacity and distance, OM3 fiber emerged. 
Features:
Optimized fiber, the optical fiber in a wavelength of 850nm to optimize bandwidth.
OM3 fiber of "effective modal bandwidth" of the specification, thereby ensuring the transmission performance of the fiber when using VCSEL laser. OM2 fiber of the "effective modal bandwidth" not required.
03 OM4 Fiber
OM3 OM4 is based on the transformation from its birth in 2009, the modal bandwidth than OM3 wider, with better performance. OM4 transmission is 40 / 100G most widely used media. 
Features:
VSCEL effective bandwidth for the transmission of laser developed than OM3 more than doubled. OM4 re-optimized on the basis of OM3, with better performance.
Fiber 04 OM5
OM5 fiber jumper is a laser-optimized multimode fiber jumpers, specifically designated wavelength division multiplexed broadband characteristics, known as a broadband fiber optic jumpers OM5 multimode fiber jumpers, for high bandwidth applications . It uses a single-mode optical wavelength division multiplexing technology, the wavelength range of the extension of the available network transmission, capable of supporting four wavelengths on a core multimode optical fiber, the optical fiber core reduce the required number of 1/4 before.
Parameter comparison
01 OM2 / OM3 / 0M4OM5 parameter specifications comparison
1, OM2 means 850 / 1300nm overfilled bandwidth of 500 / 500MHz.km 50um or more 62.5um core multimode optical fiber;
2, OM3 850nm laser is optimized multimode fiber core diameter 50um, at 10Gb / s Ethernet uses the VCSEL 850nm, the optical fiber transmission distance can reach 300m;
3, OM4 OM3 multimode fiber is an upgraded version of the optical fiber transmission distance can reach 550m.
4, OM5 fiber jumpers will increase to 6000MHZ.km 850nm effective modal bandwidth (EMB) at a wavelength in the vicinity of a wavelength of 880nm is reached 8000MHZ.km.
02 OM2 / OM3 / 0M4 / OM5 Features Comparison
1, OM2: core diameter and numerical aperture are relatively small, effectively reducing mode dispersion in multimode fiber, significant increase in bandwidth, the production costs can be reduced 1/3;
2, OM3: sheath with flame-retardant, flame propagation may be prevented, to prevent the dissemination of smoke, gas and other acid gases, and need to meet the 10 GB / s transmission rate;
3, OM4: wavelength is generally 850 / 1310nm, 1 times only support one wavelength;
4, OM5: OM5 wavelength fiber jumpers generally 850 / 1300nm, 1 can support at least four times the wavelength.
03 OM2 / OM3 / 0M4OM5 contrast transfer function
Jumper selectable
OM3 and OM4 fiber optic cabling commonly used in the data center environment, and even the transmission support 10G 40 / 100G Fast Ethernet path.
OM5 fiber jumpers to support legacy applications and OM3 / OM4 fiber as jumpers, and it is fully compatible with the OM3 and OM4 fiber jumpers strong and interoperability.