Multimode fiber optic cable

“OM” stand for optical multi-mode, that is, optical mode, is a standard for multimode fiber to indicate the level of fiber. 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 optical fibers
2. OM1 refers to 50um or 62.5um core diameter multimode fiber with a full injection bandwidth of 850/1300nm and above 200/500MHz.km;
3. OM2 refers to the 50um or 62.5um core diameter multimode optical fiber with a full injection bandwidth of 850/1300nm and above 500/500MHz.km;
4. 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;
5. OM4 is an upgraded version of OM3 multimode optical fiber, and the optical fiber transmission distance can reach 550m.

Type Fiber Diameter (μm) Fiber Type1 Gigabit Ethernet 1000BASE-SX1 Gigabit Ethernet 1000BASE-LX10Gbps Ethernet 10GBASE40Gbps Ethernet 40GBASE SR4100Gbps Ethernet 100GBASE SR4

OM162.5/125 multimode 275m550m33mNot supportedNot supported

OM250/125 multimode 550m550m82mNot supportedNot supported

OM3 (laser optimization) 50/125 multimode 550m 550m 300m 100m (SR4) 100m (SR4)

OM4 (laser optimized) 50/125 multimode 550m550m400m150m(SR4)150m(SR4)

Single-mode 9/125 single-mode 5km at 1310nm5km at 1310nm10km at 1310nmN/AN/A

2. Design comparison of OM1, OM2, OM3 and OM4 optical fibers
3. The traditional OM1 and OM2 multimode fibers use LED (Light Emitting Diode) as the basic light source 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 It is the transmission of LD (Laser Diode laser diode);
4. Compared with OM1 and OM2, OM3 has higher transmission rate and bandwidth, so it is called optimized multimode fiber or 10G multimode fiber;
5. OM4 is re-optimized on the basis of OM3, with better performance.
6. Comparison of functions and characteristics of OM1, OM2, OM3 and OM4 optical fibers
7. OM1: Large core diameter and numerical aperture, with strong light-gathering ability and anti-bending characteristics;
8. OM2: The core diameter and numerical aperture are relatively small, which effectively reduces the modal dispersion of multimode fiber, significantly increases the bandwidth, and reduces the production cost by 1/3;
9. OM3: The use of flame-retardant outer skin can prevent the spread of flames, prevent the emission of smoke, acid gas and poisonous gas, etc., and meet the needs of 10 gb/s transmission rate;
10. 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 optical fibers
5. OM1 and OM2 have been widely deployed in building applications for many years, supporting Ethernet transmission with a maximum of 1GB;
6. 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.
7. When to use OM3 fiber optic jumper?

OM3 optical fiber is an optical fiber designed to work with VCSEL, conforms to the OM-3 optical fiber specification of ISO/IEC11801-2nd, and meets the requirements of 10 Gigabit Ethernet applications. There are many types of OM3 optical fiber, including indoor type, indoor/outdoor versatility, etc., and the number of cores of the optical fiber ranges from 4 cores to 48 cores. In addition, all applications based on the old multimode 50/125 fiber are supported, including support for LED light sources and laser light sources.

1. The transmission distance of Gigabit Ethernet using OM3 optical 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 otherwise. 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 VCSEL 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 a wavelength of 1310nm in a gigabit system, and a transmission distance of 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 10 Gigabit 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 optic jumper?

For a typical link, the cost of the optical module is very expensive. Although the cost of single-mode fiber is cheaper than multimode fiber, the use of single-mode fiber requires a very expensive 1300nm optical module, and its cost is about 2-3 times that of an 850nm multimode optical module. In general, a multimode fiber The system cost of the fiber optic system is much lower than that of the single-mode fiber system.

When investing in fiber optic cabling, if you can consider increasing the initial investment of some cabling and adopt better multimode fiber, such as OM4 fiber, you can ensure that the current multimode fiber technology can be fully utilized to reduce the overall cost of the current system; when the system When it is necessary to upgrade to a higher rate system, such as 40G and 100G, OM4 can still be used and will save costs more.

In a word, when the transmission rate is greater than 1Gb/s, it is a good system choice to adopt multimode fiber. When the system requires a higher transmission rate, the following are our guidelines for choosing 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.

Summarize

Multimode fiber technology has been developed from OM1 multimode to OM4 which supports 10Gbps now, which will make the user’s investment get the most effective return and become the best choice for backbone cabling or fiber to the desktop.