Classification Table of Optical Cable Lines by Level

Optical cable line levels are classified into single-mode (OS1, OS2) and multimode (OM1–OM5) fibers, each defined by core size, transmission distance, and bandwidth performance.Single-Mode Fiber (OS)Single-mode fibers (SMF) guide light along a single path through a small core (~9µm), enabling long-distance, high-speed transmission. They are categorized as:OS1: Designed for indoor, short-distance applications such as inter-rack connections or campus backbones. Typically uses tight-buffered construction, supports speeds up to 100Gbps over 10km, and is suitable for distances up to 2km .OS2: Optimized for long-distance and outdoor applications, often in loose-tube or blown fiber constructions. Supports higher performance with lower attenuation, capable of distances from 5km to 80km depending on speed and wavelength, making it ideal for backbone networks and inter-building links .Multimode Fiber (OM)Multimode fibers (MMF) allow multiple light paths through a larger core (50–62.5µm), making them cost-effective for short-reach networks. They are classified as:OM1: 62.5µm core, standard multimode fiber, suitable for legacy 1Gbps networks over short distances (~300m at 1Gbps), .OM2: 50µm core, standard multimode fiber, supports higher bandwidth than OM1, typically used for 1–10Gbps over short distances .OM3: 50µm core, laser-optimized, supports 10Gbps up to 300m and 40/100Gbps over shorter distances, widely used in modern data centers .OM4: Enhanced 50µm fiber, supports 10Gbps up to 550m and higher-speed applications, suitable for high-density enterprise LANs .OM5: Optimized for short wavelength division multiplexing (SWDM), supports multiple wavelengths over a single fiber, future-proofing high-speed data center networks .Key Differences Between OS and OM FibersFeatureSingle-Mode (OS1/OS2)Multimode (OM1–OM5)Core Diameter~9µm50–62.5µmLight PathSingleMultipleTransmission DistanceLong (up to 80km)Short (up to 550m for high-speed MMF)Typical UseBackbone, inter-building, long-haulData centers, LANs, campus networksLight SourceLaser or laser diodeLED or laserStandards and NomenclatureThe OM/OS classification originates from ISO/IEC 11801 and TIA/EIA standards, which define fiber performance levels and cable construction. BS EN 50173 also references these categories, emphasizing their role in cabled optical fiber performance rather than just the fiber itself . Understanding these classifications helps network designers select the appropriate fiber type based on distance, bandwidth, and application requirements, ensuring optimal performance and cost-efficiency.