Types of Fibre Cables (OM1, OM2, OM3 and OM4)

Confused by the dizzying array of fiber optic cable types? We’ve got you covered! This guide dives deep into OM1, OM2, OM3, and OM4, deciphering their strengths and weaknesses to help you pick the perfect cable for your needs.

Key Takeaways:

• Speed Demons: OM3 & OM4 reign supreme for high-speeds (40Gbps & 100Gbps), while OM1 & OM2 cater to slower connections (10Mbps & 1Gbps).
• Distance Matters: OM3 & OM4 conquer longer distances, making them ideal for sprawling networks.
• Futureproofing: OM4 boasts the latest technology, ensuring it stays relevant as data demands soar.

Q: What are the differences in fiber optic cables (OM1, OM2, OM3 and OM4)

A: There are five main types of optical multimode fiber optic cables classified by the ISO 11801 standard: OM1, OM2, OM3, OM4, and OM5. They are all used for high-speed data transmission over various distances.

Q: So, which fiber optic cable should I choose?

A: It depends on your speed and distance requirements. For blazing-fast speeds over long distances, OM4 is your champion. For budget-friendly, shorter-range applications, OM1 or OM2 might be the sweet spot. Consider consulting a fiber optic specialist for tailored advice!

The transition to 40- and 100-GbE networks is being driven by the desire for more network bandwidth. Several causes are driving this need, including the expansion of global IP traffic, more switching, routing, virtualization, and data centre connections, applications requiring faster bandwidth, video-on-demand, convergence, and more.

You may need to consider your cabling infrastructure and how it will fulfil your present and future data requirements when planning your 40-/100-GbE migration. For the next 15 to 20 years, whatever you deploy must be expandable enough to fulfil the demand for higher bandwidth. The TIA recommends OM3 and OM4 laser-optimized multimode Fibre as the preferred cables for data centre connectivity.

Multiple types of graded-index multimode Fibre optic cable exist. The categories OM1, OM2, and OM3 are defined by the ISO/IEC 11801 Ed 2.1:2009 standard. The TIA/EIA acknowledges OM1, OM2, OM3, and OM4 as standards. In August 2009, the TIA/EIA ratified OM4 (TIA/EIA 492-AAAD). In June 2010, the IEEE approved OM4 (802.ba).

What is Fibre Optic cable?

OM1 and OM2

OM1 requires 62.5-micron cable, while OM2 requires 50-micron cable. These are frequently used in premises applications that handle Ethernet rates between 10 Mbps and 1 Gbps.
They are also commonly used in conjunction with LED transmitters. However, OM1 and OM2 cables are not adequate for today’s higher-speed networks.

OM3 and OM4

ISO 11801 defines OM3 as a standard. The TIA ratified OM4 in August 2009 (TIA/EIA 492-AAAD). In June 2010, the IEEE approved OM4 (802.3ba 40G/100G Ethernet). IEEE 802.3-2012 was the result of its 2012 revision. The Task Force for 802.3 bm is developing its improvements. The standard offers comprehensive instructions for 40/100 GbE transmission via OM3 and OM4 multimode Fibre optic cable as well as single-mode Fibre optic cable. Copper, OM1, and OM2 are not included.

Laser optimized

The 50-micron laser-optimized multimode Fibre (LOMMF) types OM3 and OM4 were created to support faster networks like 10-, 40-, and 100-GbE. They also provide assistance to existing networks. Laser-optimized multimode Fibre cable varies from normal multimode cable in that each assembly has graded refractive index profile Fibre optic wire. Because the refractive index of the core glass decreases near the outside cladding, light paths travel toward the fibre’s outer edge faster than other channels. This speed boost equalises travel time for both short and long light paths, ensuring accurate information transmission and delivery over much wider distances, up to 300 metres at 10 Gbps. A laser-optimized cable is aqua in colour.

Both the OM3 and OM4 feature aqua sheaths and are intended for use with 850-nm vertical-cavity surface-emitting lasers (VCSELS).

A 50-micron cable with an effective modal bandwidth (EMB) of 2000 MHz/km is required per OM3 specifications. Up to 100 metres of 100-Gbps link distance are supported.

A 50-micron high-bandwidth cable with an EMB of 4700 MHz/km is required by OM4. It is capable of 150-meter 100-Gbps link distances.

For all speeds, OM3 permits a connector loss of 1.5 dB at 100 metres; for speeds between 40 and 100 GbE, OM4 permits a connector loss of 1.0 dB at 150 metres. While being considerably less expensive to implement, OM3 and OM4 both outperform single-mode Fibre in terms of performance. Furthermore, single-mode electronics are costly.

Different types of Optical Fiber

Manufacturing process

Laser-optimized OM3 and OM4 cables are manufactured in a different manner from OM1 and OM2, which are built with a minor imperfection in the core known as an index depression. LED light sources are connected to these cables. There is no centre flaw in the production of OM3 and OM4.

The use of VCSELs increased as networks transitioned to higher speeds in contrast to LEDs, which have a maximum modulation rate of 622 Mbps and cannot be turned on and off quickly enough to serve higher-speed applications. As a result, producers altered the manufacturing procedure to fix the centre flaw and allow OM3 and OM4 cables to be used with VCSELs without any further processing.

Parallel transmission

40- and 100-GbE over OM3 and OM4 use parallel optics, in which data is transmitted and received over several Fibres at the same time. A 40-GbE network consists of four 10-Gbps Fibre channels, in each direction, for a total of eight Fibres. The 20 Fibres in 100-GbE are divided into 10 Fibre channels each way. The signals are then combined at each end in a connection with an arrayed transceiver that has 4–10 VCSELs and detectors. The Media Dependent Interface (MDI) is the MPO adaptor for multimode Fibre (IEC 61754-7).