What is the difference between om3 and om4

I get asked this question a lot by network technicians when they're deciding what kind of cable to install in their network. The major difference between OM3 and OM4 cables is bandwidth, which has a direct effect on channel distance. The chart below shows how this additional bandwidth translates to maximum operating distance.

As you can see, OM4 offers a longer maximum distance of meters versus meters for OM3. You may have also noted that the loss budget for the OM4 channel is lower by. If the various modes of light spread out too much, the receiver at the other end will have trouble decoding the signal. Modal dispersion is used to determine the modal bandwidth of the fiber. Pay attention--this is where it can get confusing.

The higher the modal dispersion, the lower the modal bandwidth. The lower the modal dispersion, the higher the modal bandwidth and the greater the amount of information that can be transmitted. This means that OM4 can transmit more information within the same distance.

Skip to main content. Americas United States. There are numerous factors at work here and your choice to figure out whether you need OM3 or OM4. But the basis is the cost versus what distances you are running. An OM3, for example, can run 10 gigabit at meters. An OM4 can run 10 gigabit at meters. Now when we go to 40 gig and gig, OM3 will be able to go meters but OM4 will be able to go meters. For both OM3 and OM4, the EMB is most effective when the distance remains at 1 kilometer or under; over 1 kilometer will slow transmission speed and distance.

Regarding compatibility, OM4 is entirely backwards compatible with OM3 fiber optics. The chart below provides detailed information on minimum modal bandwidth of OM3 and OM4 fiber. OM3 multimode fiber is specifically made for 10G Ethernet transmission. This usually makes it the prime option for 10 Gigabit Ethernet over multimode fiber applications. If a project requires an extended transmission distance, OM4 multimode is a fitting option.

Through the usage of parallel-optics transmission technology, 40G and G Ethernet can transmit and receive data simultaneously, and over multiple fiber optics. The chart below displays the maximum transmission distance of OM3 and OM4 fibers under different transmission speeds. But, there is still a debate about the when it pertains to maximum transmission distance of OM4 under 10G.