What is the difference between OM1-OM4 fibers?
"OM" stand for optical multi-mode, that is, optical mode, is a standard for multimode fibers to express fiber grades. The bandwidth and maximum distance of different levels of transmission are different, and the differences between them are analyzed from the following aspects.
1. Comparison of parameters and specifications of OM1, OM2, OM3 and OM4 fibers
1. OM1 refers to 50um or 62.5um core diameter multimode fiber with 850/1300nm full injection bandwidth above 200/500MHz.km;
2. OM2 refers to 50um or 62.5um core diameter multimode fiber with 850/1300nm full injection bandwidth above 500/500MHz.km;
3. OM3 is a 50um core diameter multimode fiber optimized by 850nm laser. In 10Gb/s Ethernet using 850nm VCSEL, the fiber transmission distance can reach 300m;
4. OM4 is an upgraded version of OM3 multimode fiber, and the fiber transmission distance can reach 550m.
2. Design comparison of OM1, OM2, OM3 and OM4 fibers
1. The traditional OM1 and OM2 multimode fibers are based on LED (Light Emitting Diode) light sources in terms of standard and design, while OM3 and OM4 are optimized on the basis of OM2, making them suitable for light sources at the same time For the transmission of LD (Laser Diode laser diode);
2. Compared with OM1 and OM2, OM3 has higher transmission rate and bandwidth, so it is called optimized multimode fiber or 10 Gigabit multimode fiber;
3. OM4 is re-optimized on the basis of OM3, with better performance.
3. Comparison of functions and features of OM1, OM2, OM3 and OM4 fibers
1. OM1: The core diameter and numerical aperture are large, and it has strong light-gathering ability and anti-bending characteristics;
2. OM2: The core diameter and numerical aperture are relatively small, which effectively reduces the modal dispersion of the multimode fiber, significantly increases the bandwidth, and reduces the production cost by 1/3;
3. OM3: The flame-retardant outer skin can prevent the spread of flame, prevent the emission of smoke, acid gas and poisonous gas, etc., and meet the needs of 10 gb/s transmission rate;
4. OM4: Developed for VSCEL laser transmission, the effective bandwidth is more than double that of OM3.
4. Application comparison of OM1, OM2, OM3 and OM4 fibers
1. OM1 and OM2 have been widely deployed in building applications for many years, supporting Ethernet transmission with a maximum value of 1GB;
2. OM3 and OM4 optical cables are usually used in the wiring environment of the data center, supporting the transmission of 10G or even 40/100G high-speed Ethernet.
5. When to use OM3 fiber patch cords?
OM3 fiber is an optical fiber designed to work with VCSELs. It conforms to the OM-3 fiber specification of ISO/IEC11801-2nd and meets the needs of 10 Gigabit Ethernet applications. There are many types of OM3 optical fibers, including indoor type, indoor/outdoor versatility, etc. The number of cores of the optical fiber ranges from 4 cores to 48 cores. All legacy multimode 50/125 fiber based applications are also supported, including support for LED light sources and laser light sources.
1. The transmission distance of Gigabit Ethernet using OM3 fiber system can be extended to 900 meters, which means that users do not need to use expensive laser devices when the distance between buildings exceeds 550 meters.
2. Within a distance of 2000 meters, standard 62.5/125μm multimode fiber can be used in various situations within the OC-12 (622Mb/s) rate range, and single-mode fiber will be used in other cases. However, the emergence of OM3 multimode fiber has changed this situation. Since OM3 fiber can increase the transmission distance of Gigabit and 10 Gigabit systems, the use of 850nm wavelength optical modules and VCSELs will be the most cost-effective wiring solution.
3. When the link length exceeds 1000 meters, single-mode fiber is still the only choice at present. Single-mode fiber can achieve a transmission distance of 5 kilometers at 1310nm wavelength in a gigabit system and 10 kilometers in a 10-gigabit system. Transmission distance.
4. When the link length is less than or equal to 1000 meters, OM3 50μm multimode fiber can be used in the gigabit system, and single-mode fiber should be used in the 10G system.
5. When the link length is less than 300 meters, OM3 multimode fiber can be used in any Gigabit and 10 Gigabit systems.
6. When to use OM4 fiber patch cords?
For a typical link, the cost of optical modules is about very expensive. Although the cost of single-mode fiber is cheaper than that of multi-mode fiber, the use of single-mode fiber requires very expensive 1300nm optical modules, and its cost is about 2-3 times that of 850nm multi-mode optical modules. The cost of the system is much lower than that of single-mode fiber systems.
When investing in fiber optic cabling, if you can consider increasing the initial investment of some cabling and use better multimode fiber, such as OM4 fiber, you can ensure that the current multimode fiber technology is fully utilized and the overall cost of the current system is reduced; when the system When you need to upgrade to higher speed systems, such as 40G and 100G, OM4 can still be used and will be more cost-effective.
In short, when the transmission rate is greater than 1Gb/s, the use of multimode fiber is a good system choice. When the system requires higher transmission rates, the following are our guidelines for selecting OM4 fiber:
1. For Ethernet users, in 10Gb/s system transmission, the transmission distance can reach 300m to 600m; in 40Gb/s and 100Gb/s systems, the transmission distance is 100m to 125m.
2.For campus network users, OM4 fiber will support 4Gb/s fiber link length of 400m, 8Gb/s fiber link length of 200m or 16Gb/s fiber link length of 130m.