Fibre Optics

Fibre Optics | Digital Transmission

How fibre optics works

Fibre optics transmit data in the form of light particles — orphotons— that pulse through a fibre optic cable. The glass fibre core and the cladding each have a different refractive index that bends incoming light at a certain angle. When light signals are sent through the fibre optic cable, they reflect off the core and cladding in a series of zig-zag bounces, adhering to a process called total internal reflection. The light signals do not travel at thespeed of lightbecause of the denser glass layers, instead traveling about 30% slower than the speed of light. To renew, or boost, the signal throughout its journey, fibre optics transmission sometimes requiresrepeatersat distant intervals to regenerate theoptical signal by converting it to an electrical signal, processing that electrical signal and re-transmitting the optical signal.

Types of fibre optic cables

Multimode fiber and single-mode fiber are the two primary types of fiber optic cable.Single-mode fibreis used for longer distances due to the smaller diameter of the glass fiber core, which lessens the possibility forattenuation– the reduction in signal strength. The smaller opening isolates the light into a single beam, which offers a more direct route and allows the signal to travel a longer distance. Single-mode fiber also has a considerably higherbandwidththan multimode fiber. The light source used for single-mode fiber is typically alaser. Single-mode fiber is usually more expensive because it requires precise calculations to produce the laser light in a smaller opening.

 Fiber Optic Cable


Fiber Optic Cables

Multimode fiberis used for shorter distances because the larger core opening allows light signals to bounce and reflect more along the way. The larger diameter permits multiple light pulses to be sent through the cable at one time, which results in more data transmission. This also means that there is more possibility for signal loss, reduction or interference, however. Multimode fibre optics typically use anLEDto create the light pulse.

While copper wire cables were the traditional choice for telecommunication, networking and cable connections for years, fibre optics has become a common alternative. Most telephone company long-distance lines are now made of fiber optic cables. Optical fiber carries more information than conventional copper wire, due to its higher bandwidth and faster speeds. Because glass does not conduct electricity, fibre optics is not subject toelectromagnetic interferenceand signal losses are minimized.

Fibre Optics

In addition, fiber optic cables can be submerged in water and are used in more at-risk environments like undersea cable. Fiber optic cables are also stronger, thinner and lighter than copper wire cables and do not need to be maintained or replaced as frequently. Copper wire is often cheaper than fibre optics, however, and is already installed in many areas where fiber optic cable hasn’t been deployed. Glass fiber also requires more protection within an outer cable than copper, and installing new cabling is labor-intensive, as it typically is with any cable installation.

Fibre optics uses

Computer networking is a common fibre optics use case, due to optical fiber’s ability to transmit data and provide high bandwidth. Similarly, fibre optics is frequently used in broadcasting and electronics to provide better connections and performance.