Brief Introduction of OM1,OM2,OM3,OM4 Optical Fiber

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.

Table 1: Bandwidth and maximum distance of various fibers in gigabit transmission:

Fiber mode	Bandwidth	Bandwidth	1Gbps distance		10Gbps distance		Fiber grade
	850nm	1300nm
	Mhz*km	Mhz*km
MM			@850nm	@1300nm	@850nm	@1300nm
Standard 62.5/125μm	200	500	275m	550m	33m	300m	OM1
Standard 50/125μm	400	800	500m	1000m	66m	450m	OM1
Standard 50/125/62.5μm	500	500	550m	550m	82m	300m	OM2
50/125μm-110	600	1200	750m	2000m	110m	850m	OM2+
50/125μm-150	700	500	750m	550m	150m	300m	OM2
50/125μm-300	1500	500	1000m	550m	300m	300m	OM3
50/125μm-550	3500	500	1000m	550m	550m	550m	N.A
SM			@1310m	@1550nm	1310/1383/1550nm
Standard 9/125μm			5000m		10000m-40000m

Table 2: Bandwidth and attenuation of various fibers

Fiber mode	Bandwidth (Mhzkm)			Attenuation (db/km)
	OFB Overfilled Bandwidth		EMB  Effective Modal Bandwidth
MM	@850nm	@1300nm	@850nm	@850nm	@1300nm
Standard 62.5/125μm	200	500	220	3.5	1
Standard 50/125μm	500	500	510	3.5	1.5
50/125μm-150	700	500	850	3.5	1.5
50/125μm-300	1500	500	2000	3.5	1.5
50/125μm-550	3500	500	4700	3	0.7
SM				@1310nm	@1550nm
Standard 9/125μm				0.3	0.4

With the cost decrease of Ethernet equipment and the increasing requirements of network applications, 10 Gigabit Ethernet is bound to be put into application. Fiber becomes the first choice to be used in 10 gigabit Ethernet due to its light weight, large capacity and transmission bandwidth. Although single mode fiber can be used in optical networking, the cost of optical transceiver is high since laser is the light source in gigabit Ethernet. VCSEL light source has been researched to use with 50/125 fiber, which would support 300 metres transmission at 850nm. Meanwhile, this application also can provide 900 metres transmission without increase the cost.

Shorter than 2000 metres, the standard 62.5/125μm multimode fiber can be used within OC-12(622Mb/s). Single mode fiber is the best choice in the rest cases. However, things have been changed since the advent of OM3 multimode fiber. Since OM3 fiber lengthens the distance of Gigabit and 10 Gigabit transmission system, 850nm wavelength window used with VCSEL will be the best selection that is highest cost-effective for arrangement of wire. When the link is more than 1000 metres, single mode fiber is still the sole choice. Single mode fiber fulfills 5 km transmission distance at 1310 wavelength in the gigabit system, while in 10 gigabit system, it can cover 10 km distance. When link is or shorter than 1000 metres, OM3 50μm multimode fiber can be used in gigabit system while single mode fiber should be used in 10 gigabit system. In addition, when link is less than 300 metres, OM3 multimode fiber is universal in both gigabit and 10 gigabit system.

GLsun Science and Tech Co.,Ltd specified in Opto-Mechanical Fiber Optical Switches manufacture since 2001. Our optical switches include 1X2, 2X2, D2X2, D2X2B, 2X2A, 2X2F, ect. Single mode, OM2, OM3 or OM4 fiber are available.