Comprehensive Multimode Fiber Optic Models

Multimode fiber is classified into five main categories—OM1, OM2, OM3, OM4, and OM5—each with distinct core sizes, bandwidths, and distance capabilities for short-range network applications.

Overview of Multimode Fiber

Multimode fiber (MMF) has a larger core diameter, typically 50 µm or 62. 5 µm, allowing multiple light modes to propagate simultaneously. This makes it ideal for short-distance communication, such as within buildings, campuses, or data centers.

MM

F uses lower-cost light sources like LEDs or VCSELs and operates mainly at 850 nm and 1300 nm wavelengths. It is generally used for distances up to 550 meters, depending on the fiber type and data rate, whereas single-mode fiber is used for longer distances due to its smaller core and lower attenuation.

Multimode Fiber Categories

Fiber Type

Core SizeJacket ColorBandwidth / Modal BandwidthMax Distance (10G Ethernet)Typical ApplicationsLight SourceOM162. 5 µmOrange200 MHz·km at 850 nm33 mLegacy 100 Mb/s networks, older buildingsLEDOM250 µmOrange500 MHz·km at 850 nm82 m1G Ethernet, limited 10GLEDOM350 µmAqua2000 MHz·km at 850 nm300 m10G Ethernet, 40G/100G short linksVCSEL (laser-optimized)OM450 µmAqua4700 MHz·km at 850 nm550 m10G/25G/40G/100G Ethernet, data centersVCSEL (enhanced laser-optimized)OM550 µmLime Green4700 MHz·km at 850 nm, supports SWDM550 mHigh-speed, wideband applications, future-proofingVCSEL, SWDM (shortwave wavelength division multiplexing)Key PointsOM1 and OM2 are older standards, primarily used in legacy networks and are LED-optimized, making them less suitable for modern high-speed applications.

OM3 and OM4 are laser-optimized multimode fibers (LOMMF), designed for VCSEL-based transceivers, supporting higher data rates and longer distances, making them the mainstream choice for modern data centers. OM5 extends OM4 capabilities by supporting shortwave wavelength division multiplexing (SWDM), allowing multiple wavelengths over a single fiber pair, which increases capacity without adding more fibers. All multimode fibers are backwards compatible with lower-speed applications, but high-speed standards like 40G and 100G Ethernet are not supported by OM1 and OM2.

Applications

Multimode fiber is widely used in: Enterprise networks for building backbone and horizontal cablingData centers for high-speed server interconnectsCampus networks for short-range connectivitySpecialized equipment like fiber optic spectroscopy or laser welding where high optical power is needed. Understanding these categories helps in selecting the right fiber type for cost-effective, high-performance network design, ensuring compatibility with current and future data rates.