How to identify multimode optical cables

Multimode optical cables can be distinguished by core size, jacket color, light source compatibility, and OM classification, which together determine bandwidth, distance, and application suitability.Core Diameter and Light PropagationMultimode fibers (MMF) feature a larger core diameter, typically 50 µm or 62.5 µm, allowing multiple light modes to propagate simultaneously. This contrasts with single-mode fibers, which have a smaller core (~9 µm) and support only one light mode. The larger core simplifies alignment and installation, making MMF cost-effective for short- to medium-distance data transmission in enterprise networks, data centers, and campus environments .OM Classification and PerformanceMultimode fibers are categorized into OM1, OM2, OM3, OM4, and OM5, each with distinct performance characteristics:OM1: 62.5 µm core, orange jacket, supports 10 Gigabit Ethernet up to ~33 meters, commonly uses LED light sources .OM2: 50 µm core, orange jacket, supports 10 Gigabit Ethernet up to ~82 meters, LED-based .OM3: 50 µm core, aqua jacket, optimized for laser sources (VCSELs), supports 10G up to 300 meters and 40/100G up to 100 meters .OM4: 50 µm core, aqua jacket, enhanced for VCSEL lasers, supports 10G up to 550 meters, 40/100G up to 150 meters .OM5: 50 µm core, lime green jacket, designed for short wavelength division multiplexing (SWDM), supporting multiple wavelengths (850–953 nm) for high-speed data transmission up to 400G/800G .Jacket Color CodingColor coding helps quickly identify multimode fiber types:OM1/OM2: OrangeOM3/OM4: AquaOM5: Lime greenSome vendors may use heather violet for enhanced OM4+ variants .Light SourcesMultimode fibers typically use LEDs or VCSELs for data transmission. LEDs are suitable for OM1 and OM2 over shorter distances, while VCSELs are used for OM3, OM4, and OM5 to achieve higher speeds and longer distances .ApplicationsMultimode fibers are ideal for short- to medium-range networks, such as:Enterprise LAN backbonesData centers (10G–400G links)Campus networksHigh-density environments requiring cost-effective, high-bandwidth connections .SummaryTo distinguish multimode optical cables, check:Core size: 50 µm vs 62.5 µmJacket color: Orange, aqua, lime greenOM type: OM1–OM5 for bandwidth and distanceLight source compatibility: LED vs VCSELApplication suitability: Short- to medium-distance, high-speed networks These factors collectively determine the cable's performance, cost, and appropriate use case, enabling proper selection and installation in modern network infrastructures .