Similarities and Differences of OM3 and OM4 Multimode Fibers

OM, short for Optical Multi-mode, refers to the multi-mode fiber grade standard. Different grades have different bandwidths and maximum transmission distances, corresponding to diverse application scenarios. In accordance with the fiber patch cord standards defined by TIA and IEC, there are five grades: OM1, OM2, OM3, OM4 and OM5. The following focuses on the similarities and differences between OM3 and OM4 fibers, which are commonly used in the market.

I. Similarities

Both OM3 and OM4 multimode fibers are widely used in local area networks (LANs), typically for backbone cabling between core networks and storage area network (SAN) switches in telecom rooms and data centers. They are both laser-optimized 50/125 multimode fibers, with a core diameter of 50 µm and a cladding diameter of 125 µm. Besides, they are paired with transceivers equipped with Vertical Cavity Surface-Emitting Lasers (VCSELs), which emit infrared light at a wavelength of 850 nm.

Figure 1: 50/125 Multimode Fiber

II. Differences

2.1 Appearance Differences

Most OM3 and OM4 fibers come with an aqua blue jacket. However, some European and U.S. companies have proposed OM4 fibers with a violet jacket. Moduletek can provide OM4 fibers in both jacket colors.

$OM3\OM4 - aqua blue color$

Figure 2: OM3/OM4 Fibers (Aqua Blue Jacket)

Figure 3: OM4 Fiber (Violet Jacket)

2.2 Transmission Performance Differences

The minimum effective mode bandwidth of OM3 fiber is 2000 MHz·km @ 850 nm, while that of OM4 fiber reaches 4700 MHz·km @ 850 nm. Thanks to its higher effective mode bandwidth, OM4 fiber patch cords can transmit more data over the same distance. The transmission distance of the same module also varies between the two fibers. For example, the SFP28-25G-SR module can transmit up to 70 m over OM3 fiber and 100 m over OM4 fiber.

2.3 Price Differences

Compared with OM3, OM4 fiber has a higher production cost and a lower production volume. Therefore, for fibers of the same length, OM4 is much more expensive than OM3.

Thus, in network construction, it is necessary to select the appropriate fiber patch cord based on actual needs to save costs and maximize the utilization of fiber resources.

Moduletek supplies the products mentioned in this application guide. Welcome to place your orders!

If you have any questions about the above content, please contact us via email: sales@moduletek.com

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Similarities and Differences of OM3 and OM4 Multimode Fibers