Types of Multimode Fiber Cable

Multimode Fiber Cable Overview

Multimode fiber optic cables are described using a system of classification determined by the ISO 11801 standard-OM1, OM2, and OM3-which is based on the modal bandwidth of the multimode optical fiber. OM4, defined in TIA-492-AAAD by the TIA, was finalized in 2009. The letters "OM" stand for Optical Multimode. OM1/OM2/OM3/OM4 fiber, technically, these categories did not define a specific fiber size, but rather their optical channel performance. More Information: multimode fiber optic cable price.

OM1 specifies 62.5-micron cable and OM2 specifies 50-micron cable. They are commonly used in premises applications supporting Ethernet rates of 10 Mbps to 1 Gbps, which are not suitable though for today's higher-speed networks. Because of their relatively large core size, they were ideal for use with LED transmitters.

OM3 and OM4 are both Laser-Optimized Multi-Mode Fiber (LOMMF) and were developed to accommodate faster networks such as 10, 40, and 100 Gbps. OM3 and OM4 specifies an 850-nm (wavelength) laser-optimized 50-micron cable.

Specifications:

OM1/OM2/OM3/OM4 can sometimes be distinguished by jacket color: orange jackets for 62.5/125 µm (OM1) and 50/125 µm (OM2), while Aqua is recommended for 50/125 µm "laser optimized" OM3 and OM4 fiber.

Comparison Between OM3 and OM4

Both OM3 and OM4 are laser optimized, high bandwidth 50µm multimode fiber. The requirements of the OM4 standard are identical to OM3 with the sole exception of the bandwidth values. Both the 850nm EMB and the 850nm Over-Filled Launch (OFL) bandwidth have been increased from the OM3 requirements as below table shows.

OM3 multimode fiber with a effective modal bandwidth of 2000 MHz/km and OM4 multimode fiber with an effective modal bandwidth of 4700 MHz/km. Why is it increased? There is a belief among some members of the standards community that the 850nm OFL bandwidth needs to be scaled along with the 850nm EMB bandwidth in order to ensure maximum performance reliability.

OM3 and OM4 are Best Options of MMF Today

Laser optimized 50µm multimode fiber is the recommended fiber type in today's LAN and Data Center environments in conjunction with 850 nm Vertical-Cavity Surface-Emitting Lasers (VCSELs). For prevailing 10Gb transmission speeds, OM3 is generally suitable for distances up to 300 meters, and OM4 is suitable for distances up to 550 meters. The vast majority of commercial buildings and data centers fall within these ranges, and because of LOMMF's lower installation and operation costs, make them the optimal choice even when considering single-mode fiber.

With the spread of 40 and 100 Gigabit Ethernet (GbE), OM3 and OM4 also are only well positioned to support these burgeoning data rates over distances of 100m and 150m, respectively. OM4 supports the majority of data center links that utilize 40 and 100 GbE in high-speed/high-performance computing applications driven by server virtualization, cloud computing, streaming video, and ever increasing IP traffic and convergence. 10GbE network core devices are slowly supplanted by 40 and 100 GbE and 40/100 GbE standards don't support previous generation OM1 and OM2 types.

Reference related documents: Multimode Fiber Optic Cables Tutorial