The world of telecommunications is rapidly moving from copper wire networks to fiber optics. Optical fiber is a very thin strand of pure glass which acts as a waveguide for light over long distances. It uses a principle known as total internal reflection. Fiber optic cable is actually composed of two layers of glass: The core, which carries the actual light signal, and the cladding, which is a layer of glass surrounding the core. The cladding has a lower refractive index than the core. This causes Total Internal Reflection within the core. Most fibers operate in duplex pairs: one fiber is used to transmit and the other is used to receive. But it is possible to send both signals over a single strand. There are two main types of fiber optic cables: Single Mode Fiber (SMF) and Multi-Mode Fiber (MMF). The difference is basically in the size of the core. MMF has a much wider core, allowing multiple modes (or “rays”) of light to propagate. SMF has a very narrow core which allows only a single mode of light to propagate. Each type of fiber has different properties with its own advantages and disadvantages.
Why use optic fiber cable?
Here are some benefits of using Fiber Optics Technology
- They have practically unlimited information
- They have high carrying capacity (very broad bandwidth, THz or Tbits/s)
- They have very low transmission losses (<0.2dB/km, cf1dB/km microwave, 10db/km twisted copper pair)
- They do not dissipate heat
- They are immune to cross-talk and electromagnetic interference