The two main types of optical fiber cables are single-mode fiber (SMF) and multimode fiber (MMF).

Single-Mode Fiber (SMF)

Single-mode fiber has a small core diameter of about 8–10 microns, allowing only a single light mode to propagate. This design minimizes signal dispersion, enabling data to travel over long distances with high bandwidth and minimal loss. SMF is commonly used in telecommunications, metro networks, and long-haul backbone connections. Within single-mode fiber, there are subtypes such as OS1 (indoor, shorter distances up to 6 miles) and OS2 (outdoor, long distances up to 125 miles), with OS2 supporting higher throughput and advanced technologies like wavelength division multiplexing (WDM) for increased network capacity .

Multimode Fiber (MMF)

Multimode fiber has a larger core diameter, typically 50µm or 62.5µm, which allows multiple light modes to travel simultaneously. This makes MMF suitable for short- to medium-range communication, such as local area networks (LANs), campus networks, and data centers. MMF supports high-speed data transmission over shorter distances, but signal dispersion can occur over longer runs, limiting its effective range compared to SMF. Common MMF types include OM1, OM2, OM3, OM4, and OM5, each offering different bandwidth and distance capabilities .

Key Differences

• Core Size: SMF ~8–10µm, MMF 50–62.5µm
• Transmission Distance: SMF supports long distances (up to 125 miles), MMF is limited to shorter distances (up to a few kilometers)
• Light Modes: SMF carries a single mode, MMF carries multiple modes
• Applications: SMF for long-haul and high-bandwidth networks, MMF for LANs and medium-range connections Understanding these two types helps in selecting the right fiber optic cable for specific networking needs, balancing distance, bandwidth, and cost considerations .