Which one is better OM2, OM3, OM4 multimode fiber?

Multimode fiber has developed from OM1 to OM5 now, so which one is better, OM2, OM3 or OM4 multimode fiber? This article will explain it to you.

Multimode fiber is mainly used for optical transmission at 850nm wavelength. Here, it can be compared from the two points of effective mode bandwidth and full injection bandwidth. Here we first understand what bandwidth is. The bandwidth of light is the product of the modulation frequency of the maximum modulation frequency pulse that can pass through a section of optical fiber and the length of the optical fiber. , the optical cable at 850nm is required to reach at least 200MHz bandwidth, the optical transmitter of OM3 optical cable is VCSEL (Vertical Cavity Surface Emitting Laser), and the optical cable is required to reach 2000MHz at 850nm. At present, the bandwidth of optical fiber is only available in multi-mode fiber, while the bandwidth of single-mode fiber is unlimited.

The effective modal bandwidth of OM2 is 950 MHz·km, and the full injection bandwidth is 700 MHz·km; the effective modal bandwidth of OM3 is 2000 MHz·km, and the full injection bandwidth is 1500 MHz·km; the effective modal bandwidth of OM4 is 4700 MHz·km , the full injection bandwidth is 4700 MHz•km. Basically, every level of multimode fiber, its performance will be improved in all aspects.

The fiber core of OM2 is conventional 50/125um; OM3 is 50um core diameter multimode fiber optimized by 850nm laser, mainly used in 10Gb/s Ethernet transmission of 850nm VCSEL laser, the fiber transmission distance can reach 300m; OM4 is OM3 The upgraded version, it optimizes the differential mode delay (DMD) generated by OM3 multimode fiber during high-speed transmission, so the transmission distance is greatly improved, and the fiber transmission distance can reach 550m.

OM2 multimode fiber is often used in multimode optical modules with a transmission rate below 10G (excluding 10G), while OM3 and OM4 multimode fibers are used in multimode optical modules with a transmission rate of 10G and above. If OM4 fiber is used for transmission, Usually the transmission distance will be longer than with OM3. From the comprehensive consideration of transmission performance and transmission distance, multimode OM4 fiber is the best compared to OM3 and OM2, followed by OM3, and finally OM2. OM3 and OM4 are mainly used in data center multimode cabling systems, and OM2 will be used later. gradually eliminated.