Understanding Fiber Optic Technology

Globally, the deployment of fiber optic cables has been rapidly increasing as the demand for high-speed and reliable data transmission, via optical fiber, continues to grow. Fiber has become the technology of choice for delivering internet and network services, as well as bridging the “last-mile” gap from operator’s equipment to homes, businesses, and enterprises. Fiber optics is a technology that uses optical fibers to transmit data as light signals, delivering high bandwidth, electromagnetic immunity, and low signal loss. Both indoors and outdoors, fiber optic cables are deployed to serve a wide range of applications, from communications to medical imaging.

What is fiber optics?

Fiber optics, or optical fiber, refers to the technology that transmits information as light pulses along a glass or plastic fiber. A fiber optic cable can contain a varying number of these glass fibers from a few up to a couple hundred. Another glass layer, called cladding, surrounds the glass fiber core. The buffer tube layer protects the cladding, and a jacket layer acts as the final protective layer for the individual strand. Fiber optics is used for long-distance and high-performance data networking. It is also commonly used in telecommunication services, such as internet, television and telephones.

Components of an Fiber optical cable

  • Core: cylindrical glass that forms the central part of the optical fiber, where light signals are transmitted. The core is made of high-purity glass (silicon dioxide) and has a higher refractive index than the cladding, so that light passes only through the core
  • Cladding: an outer coating layer that surrounds the core and reflects light back into the core, preventing the light from leaking out of the core. The cladding is made from less pure glass and has a lower refractive index than the core, which helps to keep the light signals in the core, ensuring that they travel along the fiber with minimal loss or dispersion
  • Jacket: an outer protective layer of the optical fiber made of a tough, flexible polymer material such as PVC (polyvinyl chloride) or plastic. The jacket, also known as a sheath, protects the core and cladding from mechanical damage, moisture, and abrasion.

The role of WDM in fiber optic networks

Wavelength Division Multiplexing (WDM) is the technology used in transceivers for transporting different data streams simultaneously over a single fiber optic cable. This means that a single optical fiber can be used for multiple data services instead of having to use one fiber per service. As a result, the ROI from each fiber optic cable is maximized by enabling increases in bandwidth and distance. In a WDM-based fiber optic network, transceivers play a key role by converting each data stream into a unique wavelength. This is what makes it possible for WDM solutions to improve the bandwidth and efficiency of each fiber by transporting multiple data services in parallel on a single fiber or fiber pair.

Transponders are another way of deploying WDM systems in fiber optic networks by sending and receiving optical signals over a fiber optic cable. They do this by converting short-range signals from a switch into long-range WDM signals. Transceivers are smaller, simpler and consume less power while transponders are more effective for longer distances and more customizable for meeting complex fiber optic networking requirements.

Multiplexers also play a key role in optimizing WDM-based fiber optic networks. This is done by consolidating the data streams and allowing for several stream to be transmitted over a single fiber. Reconfigurable Optical Add-Drop Multiplexers (ROADMS) are an efficient, convenient and popular type of multiplexer for customizing WDM signals in fiber optic networks. A ROADM does this with the capability to add, drop, pass and redirect wavelengths carrying data channels.

Coarse and Dense Wavelength Division Multiplexing (CWDM and DWDM) are the two main types of WDM. DWDM has become increasingly popular because it multiplexes data into even more wavelengths and can support much further distances with amplification. Both CWDM and DWDM use narrow band wavelengths and support the simultaneous transmission of any mix of SAN, WAN, voice and video data services in a fiber optic network.

Types of fiber optic cables

Single-mode fiber

Single-mode fiber is used for longer distances due to the smaller diameter of the glass fiber core. This smaller diameter lessens the possibility for attenuation, which is a reduction in signal strength. The smaller opening isolates the light into a single beam, offering a more direct route and enabling the signal to travel a longer distance.

Single-mode fiber also has a considerably higher bandwidth than multimode fiber. The light source used for single-mode fiber is typically a laser. Single-mode fiber is usually more expensive as it requires precise calculations to produce the laser light in a smaller opening.

Multimode fiber

Multimode fiber is used for shorter distances because the larger core opening enables 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 there is more possibility for signal loss, reduction or interference, however. Multimode fiber optics typically uses an LED to create the light pulse.

Advantages of fiber optics

Fiber optic cables are used mainly for their advantages over copper cables. Advantages include the following:

  • They support higher bandwidth capacities.
  • Light can travel further without needing as much of a signal boost.
  • They are less susceptible to interference, such as electromagnetic interference.
  • They can be submerged in water.
  • Fiber optic cables are stronger, thinner and lighter than copper wire cables.
  • They do not need to be maintained or replaced as frequently.

Disadvantages of fiber optics

  • Copper wire is often cheaper than fiber optics.
  • Glass fiber requires more protection within an outer cable than copper.
  • Installing new cabling is labor-intensive.
  • Fiber optic cables are often more fragile. For example, the fibers can be broken or a signal can be lost if the cable is bent or curved around a radius of a few centimeters.

Fiber optics uses

Computer networking and broadcasting

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

Internet and cable television

Internet and cable television are two of the more commonly found usages of fiber optics. Fiber optics can be installed to support long-distance connections between computer networks in different locations.


fiber optics are used in the main branches of military (army, navy, air force) for communication and data transmission. For example, these include command-and-control links on vessels and airplanes, communication links between satellite ground stations and data centers, and connections for tactical command post communications


Fiber optics is frequently used in a variety of medical instruments to provide precise illumination. It also increasingly enables biomedical sensors that aid in minimally invasive medical procedures. Because optical fiber is not subject to electromagnetic interference, it is ideal for various tests like MRI scans. Other medical applications for fiber optics include X-ray imaging, endoscopy, light therapy and surgical microscopy.


fiber optics are used in physical security applications like the perimeter fencing of data centers, whereby optical fiber can sense if someone is nearby or touches the fence. While surveillance systems use fiber optics to transmit high-definition video over long distances.

Visit Hubtech Limited for any fiber related consult or purchase.

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