Tag Archives: OM4 cable

Five Reasons To Say No To OM1 Fiber


OM1 fiber “In the multimode fiber sales in North America and around the world are occupied by more than 25% and more than 30%.” Now the question is, why users are suggested to not install 62.5 μm (OM1) fiber in their networks?

The five common reasons that users do not install OM1 fiber:

1. This is just a low-speed network cable extension. If it is more installation is only passive connection (for example, if the new OM1 cable is actually connect to any active devices), using OM3 or OM4 cables. When it comes to upgrade a low-speed link, the new OM3/OM4 fiber can remain in place, but may need to replace the old OM1 cable.

2. OM1 works well in today’s installing speed. Cabling installation means – and it is expected – will last 10 to 25 years. From now on, you will be still running the same speed of 10 to 25 years? The typical network equipment replacement cycle is five years, during the lifetime of optical cable your newly installed, you can expect 2 to 5 times equipment renewal.

3. OM1 is currently assigned. General specification provides a guide for suppliers, but if they do not update, including the recent improvements in technology, they are of limited value. If the current specification has not been updated recently, it can not work well for users.

4. OM1 is cheaper than OM3 cables or om4 cable. Based on the cost first on this is true. But the installation costs are almost the same, sometimes OM1 is higher. And if (or when) for equipments support higher speed must replace OM1, the initial savings are gone.

5. OM1 fiber has a better macrobend performance than 50 μm. Historically, in many cases it is correct for the fiber itself and fiber optic cabling. However, 50 μm fiber cabling attenuation is better than that of 62.5 μm OM1. In addition, the launched bending optimization or bend insensitive multimode fiber making the 50 μm macrobend performance is far superior to 62.5 μm OM1.

Multimode OM4 Cable Is Available For 40G Or 100G applications


There are different categories of graded-index multimode glass fiber cable, including OM1, OM2, OM3 and OM4 cables (OM stands for optical multi-mode). OM1 specifies 62.5-micron cable and OM2 specifies 50-micron cable. These are commonly used in premises applications for shorter reach 1Gb/s networks. But OM1 and OM2 cable are not suitable for today’s higher-speed networks. OM3 and OM4 are both laser-optimized multimode fiber (LOMMF) and were developed to accommodate faster fiber optic networking such as 10, 40, and 100 Gbps. Both are designed for use with 850-nm VCSELS (vertical-cavity surface-emitting lasers) and have aqua sheaths.

OM3 specifies an 850-nm laser-optimized 50-micron cable with an effective modal bandwidth (EMB) of 2000 MHz/km. It can support 10-Gbps link distances up to 300 meters. OM4 specifies a high-bandwidth 850-nm laser-optimized 50-micron cable an effective modal bandwidth of 4700 MHz/km. It can support 10-Gbps link distances of 550 meters. 100 Gbps distances are 100 meters and 150 meters, respectively.

What Makes OM4 Different?

OM4 fiber, with its higher bandwidth, has an extremely precise refractive index profile, virtually free of perturbations or defects. Just like OM3, OM4 is a 50-micron, considered to be laser-optimized multimode fiber for use with VCSELs. The key difference of OM4 from OM3 is in the refractive index of the fiber, which is more precisely graded to better equalize the arrival time of the light modes traveling at various speeds along the core of the fiber. Mode equalization depends on how well the graded index profile is constructed during fiber manufacturing. The better the modes are equalized, the higher the bandwidth of the fiber. This translates to higher bandwidth and a 550-meter reach for 10Gb/s (with some vendors claiming a 600-meter reach) and a 150-meter reach for 40/100 Gig, compared to 300 and 100 meters respectively for OM3.

You can use OM2 fiber with VCSELs, but its performance is limited to 550 meters at 1 Gb/s and only 82 meters at 10 Gb/s, compared to OM4 fiber’s reach of over 1000 meters at 1 Gb/s and 550 meters at 10 Gb/s.

OM3 and OM4 fibers are selected as the only multimode fiber for 40G/100G applications, which are the development trends of fiber optic communication. The 40G and 100G speeds are currently achieved by bundling multiple channels together in parallel with special multi-channel (or multi-lane) connector types. This standard defines an expected operating range of up to 100m for OM3 and up to 150m for OM4 for 40 Gigabit Ethernet and 100 Gigabit Ethernet. The OM3 and OM4 fibers are optimized for 850-nm transmission and have a minimum 2000 MHz.km and 4700 MHz.km effective modal bandwidth (EMB), respectively. Two EMB measurement techniques are used today for the bandwidth measurement. The minimum effective modal bandwidth calculated (EMBc) method, in our opinion, offers a more reliable and precise measurement compared to the differential mode delay (DMD) mask technique. With minEMBc, a true scalable bandwidth value is calculated that can reliably predict performance for different data rates and link lengths. With a connectivity solution using OM3 and OM4 fibers that have been measured using the minEMBc technique, the optical infrastructure deployed in the data center will meet the performance criteria set forth by IEEE for bandwidth.

OM4 cable is also especially well suited for shorter reach data center and high performance computing applications, which is the best option for the small percentage for users running 10Gb/s over links between 300 and 550 meters (or the even smaller percent who anticipate running 40 or 100Gb/s between 100 and 150 meters).