Fiber optic cables are classified by how they transmit signals and by their internal structure. Each type has distinct properties, advantages, and ideal uses.
By Transmission: Single-mode Fiber (SMF)
- Structure — a very small core of about 8–10 microns, wrapped in cladding that reflects light back into the core.
- Transmission — light travels a single path, driven by laser.
- Uses — long-haul telecom networks such as international internet links, data center interconnects, and MANs.
- Advantages — reaches tens to hundreds of kilometers with minimal signal loss and latency.
By Transmission: Multi-mode Fiber (MMF)
- Structure — a larger core of about 50–62.5 microns.
- Transmission — light travels multiple paths simultaneously, using LED light sources.
- Uses — in-building LANs, data centers, and CCTV systems.
- Advantages — high bandwidth across multiple paths at lower cost than single-mode.
Five Structural Types
1. Tight-buffered Fiber
- Fiber wrapped in a dense protective buffer coating; flexible and pressure-resistant.
- Used indoors, in LANs and data centers.
- Advantages — easy to install, resists dust and impact, lightweight.
2. Loose-tube Fiber
- Fibers sit inside loose tubes filled with gel that blocks moisture and vibration.
- Used outdoors, on utility poles and underground runs.
- Advantages — moisture-proof and tolerant of thermal expansion.
3. Armored Fiber
- Wrapped in steel or aluminium armor.
- Used where impact or animal damage is a risk, such as underground.
- Advantages — protects against impact and rodent damage; suits heavy-traffic areas.
4. Aerial Fiber
- Designed for mounting on power poles or messenger wire.
- Used in ISP networks and fiber-to-the-home (FTTH) drops.
- Advantages — easy installation, no excavation costs.
5. Ribbon Fiber
- Many fibers arranged side by side in a flat ribbon.
- Used in data centers with dense equipment interconnects.
- Advantages — moves large volumes of data in limited space.