What is fiber optics: a complete guide to this technology

Definition and operating principle of fiber optics

What exactly is optical fiber?

An optical fiber is a cable made of extremely fine glass or plastic wire, with a diameter comparable to that of a human hair. This wire, known as the core, is capable of carrying information in the form of light signals at dizzying speeds over very long distances. The core of the fiber is surrounded by an optical cladding that confines the light inside by a phenomenon known as total internal reflection.

The basic principle is based on the transmission of digital data converted into light pulses. These pulses travel through the glass wire, bouncing off the inner walls, enabling a considerable amount of information to be transported with minimal signal loss, even over several kilometers.

How fiber transmission works

Fiber optic transmission uses the principle of light refraction. When a digital signal (0 or 1) is to be transmitted, it is converted into a light pulse by a laser or LED emitter. This light propagates through the core of the fiber, continuously reflecting off the cladding, which has a different refractive index.

At the other end of the fiber, a photoreceiver captures these light pulses and converts them back into a digital electrical signal. This process enables transmission speeds of up to several terabits per second on the most efficient infrastructures, and up to 8 Gbit/s for today's residential connections.

The different types of optical fiber

Single-mode fiber

Single-mode fiber, also known as SMF (Single Mode Fiber), has a very thin core, generally 9 micrometers in diameter. It allows only one mode of light propagation through, hence its name. This feature enables it to transmit data over very long distances (several tens of kilometers) without amplifying the signal.

Single-mode fiber is mainly used for long-distance telecommunications networks, links between telephone exchanges and FTTH (Fiber To The Home) Internet connections that reach your home. It offers very high bandwidth and minimal signal attenuation.

Multimode fiber

Multimode fiber has a larger core, generally 50 or 62.5 micrometers in diameter. It allows several modes of light to propagate simultaneously through the cable. Although this configuration allows the use of less expensive light sources (LEDs rather than lasers), it limits the transmission distance to a few hundred meters due to modal dispersion.

This fiber is commonly used for corporate LANs, data centers and installations requiring high-speed connections over short distances. It represents a cost-effective solution for private infrastructures.

The advantages of fiber optics

Exceptional flow rates

The most obvious advantage of fiber optics lies in its performance in terms of throughput. Where a conventional ADSL connection is generally limited to between 1 and 20 Mbit/s, and coaxial cable to between 100 and 500 Mbit/s, fiber optics offer symmetrical speeds of up to 1, 2, 5 or even 8 Gbit/s for consumer offers.

These speeds make it possible to download a high-definition film in a matter of seconds, play online games without latency, hold 4K video conferences, or manage several simultaneously connected devices without slowing down. For professionals, this bandwidth facilitates collaborative working, cloud backups and the transfer of large files.

Minimal latency

Latency, or response time, is the delay between sending a request and receiving a response. With fiber optics, this latency is reduced to a minimum thanks to the speed at which light propagates through glass. Latency is generally less than 10 milliseconds, compared with 30 to 50 milliseconds for ADSL.

This feature is crucial not only for gamers looking for optimum responsiveness, but also for professional applications requiring real-time exchanges, such as telemedicine, remote monitoring or remote plant control.

Superior reliability and durability

Unlike the copper cables used for ADSL, optical fiber is not sensitive to electromagnetic interference. It is more resistant to temperature variations, humidity and harsh weather conditions. Its lifespan is estimated at several decades without significant performance degradation.

Fiber optics also offer remarkable connection stability, with no variation in throughput linked to distance from the telephone exchange, a recurring problem with ADSL. Whether you're 100 meters or several kilometers from the connection point, the throughput remains the same.

Symmetrical flow

A major advantage of fiber optics is its symmetrical speeds, i.e. identical download and upload speeds. Whereas ADSL generally offers very limited upload speeds (1 to 2 Mbit/s), fiber allows files to be sent as quickly as they are received.

This feature is particularly appreciated by teleworkers who regularly need to share large documents, content creators who publish videos, or companies that back up their data in the cloud.

Different deployment technologies

FTTH (Fiber To The Home)

FTTH, or fiber-to-the-home, is the most advanced technology. In this case, the optical fiber is deployed from the optical connection node (NRO) to the optical termination point (PTO) located directly at the subscriber's premises, usually in the home or office.

This configuration guarantees optimum performance, since the entire route is in optical fiber, with no copper sections. This technology is being massively deployed in France as part of the Plan France Très Haut Débit.

FTTB (Fiber To The Building)

FTTB, or fiber-to-the-building, takes the optical fiber to the building's equipment room. From there, distribution to each apartment can be via coaxial cable or twisted pair (copper). This solution is sometimes used in older buildings where vertical wiring is difficult to modify.

Performance remains very good, although slightly lower than for pure FTTH, with speeds that can reach several hundred megabits per second depending on the quality of the internal cabling.

FTTLA (Fiber To The Last Amplifier)

FTTLA is a hybrid technology used mainly by cable operators. Fiber optics are deployed right up to the last amplifier in the network, then final distribution to households is handled by the existing coaxial cable network.

This approach makes it possible to modernize existing cable networks at lower cost, offering data rates of up to 1 Gbit/s, although performance may vary depending on network load and the quality of the coaxial cabling.

Installation and equipment

Fibre optic connection

The installation of fiber optics requires the intervention of a certified technician who makes the connection from the external connection point to your home. Fiber optic cable is usually routed through existing telephone ducts or through a discreet hole.

The optical termination point (PTO) or optical box is installed inside your home, usually near your electrical panel or in the hallway. This box acts as an interface between the operator's network and your indoor installation.

The fiber box and its features

The Internet box supplied by your operator is specially designed for fiber optics. It incorporates an ONT (Optical Network Terminal) module that converts optical signals into electrical signals that can be used by your equipment. The box then distributes the Internet connection via Wi-Fi and Ethernet ports.

Modern fiber boxes generally integrate Wi-Fi 6 or 6E for optimum wireless performance, several gigabit Ethernet ports, and sometimes home automation or network storage functions. They require a power supply and must be positioned to optimize Wi-Fi coverage.

Optimizing your electrical installation

To take full advantage of your fiber connection, we recommend that you have a suitable electrical installation. Make sure the electrical outlet supplying your box is of good quality and protected by a dedicated circuit breaker. The use of an inverter can be judicious to protect your equipment from power cuts and surges.

For professional installations or homes with many connected devices, consider RJ45 Ethernet cabling in the various rooms. This solution guarantees stable, maximum data rates for your fixed equipment such as computers, game consoles or connected TVs.

Fiber optic applications and uses

For private customers

Fiber optics are transforming the digital home experience. Video streaming in 4K or 8K becomes fluid on multiple screens simultaneously, downloading video games or software updates is almost instantaneous, and automatic backup of your personal data to the cloud takes place in the background without slowing down your browsing.

Connected objects (security cameras, smart thermostats, voice assistants, connected lighting) work optimally without saturating bandwidth. Teleworking becomes more comfortable thanks to professional-quality videoconferencing and seamless access to company resources.

For professionals

Businesses benefit from fiber optics for their day-to-day activities: fast transfer of large files, multiplex video conferencing, access to cloud applications (CRM, ERP, collaborative office automation), data backup and restoration.

Creative professions (video editing, graphic design, architecture) particularly benefit from symmetrical bandwidths to share their productions. Retailers can deploy contactless payment, real-time inventory management or high-definition video surveillance systems without compromising their Internet connection.

Home automation and the connected home

Fiber optics are the ideal infrastructure for a high-performance connected home. It easily supports the proliferation of intelligent equipment: connected heating system, remote-controlled LED lighting, automated roller shutters, video door entry system, alarm system with IP cameras.

Generous bandwidth also enables the use of voice assistance services, music streaming in any room, and even energy monitoring systems that analyze and optimize your power consumption in real time. These technologies require a stable, high-performance connection that only fiber can guarantee over the long term.

The future of fiber optics

Technological developments

Optical fiber continues to evolve, with research focused on increasing data rates through new modulation and multiplexing techniques. Laboratories are already testing transmissions reaching several petabits per second on a single fiber, paving the way for applications unimaginable today.

The integration of artificial intelligence into optical network management will enable automatic performance optimization, predictive fault detection and dynamic bandwidth allocation according to need. Fiber will become even more reliable and efficient over the years.

Territorial deployment

In France, the aim is to cover 100% of the country with ultra-high-speed broadband by 2025, with priority given to FTTH. This massive rollout will gradually transform rural areas and provide equal access to digital services throughout the country.

Public and private initiatives are converging to speed up deployment, in the knowledge that fiber optics is an infrastructure as essential to our digital society as electricity or drinking water. Businesses and homes benefiting from a fiber connection even see their real estate value increase.

Conclusion

Fiber optics are much more than just a technical improvement to our Internet connections. It's a veritable technological revolution, redefining our relationship with digital technology and opening up unprecedented possibilities for individuals and professionals alike. Its exceptional performance in terms of throughput, latency and reliability make it the communications infrastructure of the present and future.

Whether you want to enjoy an optimal digital entertainment experience, expand your business, or equip your home with high-performance home automation solutions, fiber optics is the essential foundation. Its gradual roll-out throughout France guarantees equitable access to the opportunities offered by the digital world, and contributes to the economic attractiveness of our regions.

At Domeashop, we support this digital transition by offering a complete range of equipment and solutions to optimize your electrical and home automation installation and make the most of your fiber connection. Don't hesitate to consult our experts to adapt your infrastructure to your specific needs.