What Is Optical Networking? Complete Explanation

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Optical networking is a technology that uses light signals to transmit data through fiber-optic cables. It encompasses a system of components, including optical transmitters, optical amplifiers, and fiber-optic infrastructure to facilitate high-speed communication over long distances.

This technology supports the transmission of large amounts of data with high bandwidth, enabling faster and more efficient communication compared to traditional copper-based networks.

Main components of optical networking

The main components of optical networking include fiber optic cables, optical transmitters, optical amplifiers, optical receivers, transceivers, wavelength division multiplexing (WDM), optical switches and routers, optical cross-connects (OXCs), and optical add-drop multiplexers (OADMs).

Fiber optic cables

Fiber optic cables are a type of high-capacity transmission medium with glass or plastic strands known as optical fibers. 

These fibers carry light signals over long distances with minimal signal loss and high data transfer rates. A cladding material surrounds the core of each fiber, reflecting the light signals back into the core for efficient transmission.

Fiber optic cables are widely used in telecommunications and networking applications due to immunity to electromagnetic interference and reduced signal attenuation compared to traditional copper cables.

Optical transmitters

Optical transmitters convert electrical signals into optical signals for transmission over fiber optic cables. Their primary function is to modulate a light source, usually a laser diode or light-emitting diode (LED), in response to electrical signals representing data.

Optical amplifiers

Strategically placed along the optical fiber network, optical amplifiers boost the optical signals to maintain signal strength over extended distances. This component compensates for signal attenuation and allows the distance signals to travel without expensive and complex optical-to-electrical signal conversion.

The primary types of optical amplifiers include:

  • Erbium-doped fiber amplifier (EDFA): EDFAs employ erbium-doped optical fiber. When exposed to light at a specific wavelength, erbium ions within the fiber absorb and re-emit photons, amplifying the optical signal. Typically used in the 1550 nm range, EDFA is a key component for long-haul communication.
  • Semiconductor optical amplifier (SOA): SOAs amplify optical signals through semiconductor materials. Incoming optical signals induce stimulated emission within the semiconductor, resulting in signal improvement. SOAs specialize in short-range and access network scenarios.
  • Raman amplifier: Raman amplifiers use the Raman scattering effect in optical fibers. Pump light at a different wavelength interacts with the optical signal, transferring energy and intensifying it. This type of amplifier is versatile and can operate at various wavelengths, including the commonly used 1550 nm range.

Optical receivers

At the reception end of the optical link, optical receivers transform incoming optical signals back into electrical signals.


Transceivers, short for transmitter-receiver, are multifunctional devices that combine the functionalities of both optical transmitters and receivers into a single unit, facilitating bidirectional communication over optical fiber links. They turn electrical signals into optical signals for transmission, and convert received optical signals back into electrical signals.

Wavelength division multiplexing (WDM)

Wavelength division multiplexing (WDM) allows the simultaneous transmission of multiple data streams over a single optical fiber. The fundamental principle of WDM is to use different wavelengths of light to carry independent data signals, supporting increased data capacity and effective utilization of the optical spectrum.

WDM is widely used in long-haul and metro optical networks, providing a scalable and cost-effective solution for meeting the rising demand for high-speed and high-capacity data transmission.

Optical add-drop multiplexers (OADMs)

Optical add-drop multiplexers (OADMs) are major components in WDM optical networks, offering the capability to selectively add (inject) or drop (extract) specific wavelengths of light signals at network nodes. OADMs help refine the data flow within the network.

Optical switches and routers

Both optical switches and routers contribute to the development of advanced optical networks with solutions for high-capacity, low-latency, and scalable communication systems that can meet the changing demands of modern data transmission.

  • Optical switches selectively route optical signals from one input port to one or more output ports. They are important in establishing communication paths within optical networks. These devices work by controlling the direction of optical signals without converting them into electrical signals.
  • Optical routers, on the other hand, direct data packets at the network layer based on their destination addresses. They operate in the optical domain, maintaining the integrity of the optical signals without converting them into electrical form.

Optical cross-connects (OXCs)

Optical cross-connects (OXCs) enable the reconfiguration of optical connections by selectively routing signals from input fibers to desired output fibers. By streamlining wavelength-specific routing and rapid reconfiguration, OXCs contribute to the flexibility and low-latency characteristics of advanced optical communication systems.

How optical networking works

Optical networking functions by harnessing light signals to transmit data through fiber-optic cables, creating a rapid communication framework. The process involves light signal generation, light transmission, data encoding, light propagation, signal reception and integration, and data processing.

Infographic showing the 6 steps of optical networking, starting with light signal generation.

1. Light signal generation

The optical networking process begins by converting data into light pulses. This conversion is typically achieved using laser sources to secure the successful representation of information.

2. Light transmission

The system sends light pulses carrying data through a fiber optic cable during this phase. The light travels within the cable’s core, bouncing off the surrounding cladding layer due to total internal reflection. This lets the light travel great distances with minimal loss.

3. Data encoding

Data is then encoded onto the light pulses, introducing variations in either the light’s intensity or wavelength. This process is tailored to meet the needs of business applications, ensuring a seamless integration into the optical networking framework.

4. Light propagation

The light pulses propagate through the fiber-optic cables, delivering high-speed and reliable connectivity within the network. This results in the swift and secure transmission of important information between different locations.

5. Signal reception and integration

At the receiving end of the network, photosensitive devices, like photodiodes, detect the incoming light signals. The photodiodes then convert these light pulses back into electrical signals, improving optical networking integration.

6. Data processing

The electrical signals undergo further processing and interpretation by electronic devices. This stage includes decoding, error correction, and other operations necessary to guarantee the data transmission accuracy. The processed data is used for various operations, supporting key functions, such as communication, collaboration, and data-driven decision-making.

8 types of optical networks

There are many different types of optical networks serving diverse purposes. The most commonly used ones are mesh networks, passive optical network (PON), free-space optical communication networks (FSO), wavelength division multiplexing (WDM) networks, synchronous optical networking (SONET) and synchronous digital hierarchy (SDH), optical transport network (OTN), fiber to the home (FTTH)/fiber to the premises (FTTP), and optical cross-connect (OXC).

1. Mesh networks

Optical mesh networks interconnect nodes through multiple fiber links. This provides redundancy and allows for dynamic rerouting of traffic in case of link failures, enhancing the network’s reliability.

  • Typical use: Often used in large-scale, mission-critical applications where network resilience and redundancy are essential, such as in data centers or core backbone networks.

2. Passive optical network (PON)

PON is a fiber-optic network architecture that brings optical cabling and signals to the end user. It uses unpowered optical splitters to distribute signals to multiple users, making it passive.

  • Typical use: “Last-mile” connectivity, providing high-speed broadband access to residential and business users. 

3. Free-space optical communication (FSO)

FSO uses free space to transmit optical signals between two points.

  • Typical use: High-speed communication in environments where it is impractical or challenging to lay optical fibers, such as urban areas or military purposes.

4. Wavelength division multiplexing (WDM)

WDM uses different wavelengths of light for each signal, allowing for increased data capacity. Sub-types of WDM include coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM).

  • Typical use: CWDM is used for short-distance, metro-area networks, while DWDM is for long-haul and high-capacity communication.

5. Synchronous optical networking (SONET)/synchronous digital hierarchy (SDH)

SONET and SDH are standardized protocols for transmitting large amounts of data over long distances using fiber-optic cables. North America more commonly uses SONET, while international industries use SDH.

  • Typical use: SONET and SDH are designed for high-speed, long-distance transmission of voice, data, and video. They offer a synchronous and reliable transport infrastructure used in telecommunications backbones and carrier networks.

6. Optical transport network (OTN)

OTN transports digital signals in the optical layer of communication networks. It comes with functions like error detection, performance monitoring, and fault management features.

  • Typical use: Used together with WDM to maximize the resilience of long-haul transmissions.

7. Fiber to the home (FTTH)/fiber to the premises (FTTP)

FTTH and FTTP refer to the deployment of optical fiber directly to residential or business premises, providing high-speed internet access.

  • Typical use: FTTH and FTTP support bandwidth-intensive applications like video streaming, online gaming, and other broadband services.

8. Optical cross-connect (OXC)

OXC facilitates the switching of optical signals without converting them to electrical signals.

  • Typical use: Mostly used in large-scale optical networks by telecommunication carriers to manage traffic.

How optical networking is used today

Various industries and domains today use optical networking for high-speed and efficient data transmission. These include telecommunications, healthcare, financial organizations, data centers, internet service providers (ISPs), enterprise networks, 5G networks, video streaming services, and cloud computing.

Infographic listing common uses for optical networking, including telecommunications, healthcare, ISPs, and cloud computing.


Optical networking is the foundation of phone and internet systems. Today, optical networking remains pivotal in telecommunications, connecting cell sites, ensuring high availability through dynamic traffic rerouting, and enabling high-speed broadband in metropolitan areas and long-distance networks.


For healthcare, optical networking guarantees rapid and secure transmission of medical data, expediting remote diagnostics and telemedicine services.

Financial organizations

Financial organizations use this technology for fast and safe data transmission, which is indispensable for activities like high-frequency trading and connecting branches seamlessly.

Data centers

Optical networking in data centers links servers and storage units, offering a high-bandwidth and low-latency infrastructure for reliable data communication.

Internet service providers (ISPs)

Internet service providers (ISPs) employ optical networking to offer broadband services, using fiber-optic connections for quicker internet access.

Enterprise networks

Large businesses use internal optical networking to connect offices and data centers, maintaining high-speed and scalable communication within their infrastructure.

Mobile networks (5G)

For 5G mobile networks, optical networking allows for increased data rates and low-latency requirements. Fiber-optic connections link 5G cell sites to the core network, bringing bandwidth for diverse applications. 

Video streaming services

Optical networks enable smooth data transmission to deliver high-quality video content via streaming platforms for a more positive viewing experience.

Cloud computing

Cloud service providers rely on optical networking to interconnect data centers to give scalable and high-performance cloud-based services.

History of optical networking

The collaborative efforts of several optical networking companies and distinguished individuals have significantly shaped the optical networking landscape as we know it today.

  • 1792: French inventor Claude Chappe invented the optical semaphore telegraph, one of the earliest examples of an optical communication system.
  • 1880: Alexander Graham Bell patented the Photophone, an optical telephone system. However, his first invention, the telephone, was deemed to be more practical.
  • 1966: Sir Charles K. Kao and George A. Hockham proposed that fibers made of ultra-pure glass could transmit light for distances of kilometers without a total loss of signal.
  • 1996: The first commercially available 16-channel DWDM system was introduced by Ciena Corporation.
  • 1990s: Organizations began to use fiber optics in enterprise local area networks (LANs) to connect Ethernet switches and IP routers.
    • Rapid expansion of optical networks to support the growing demand driven by the internet boom.
    • Organizations began to use optical amplification to decrease the need for repeaters, and more businesses implemented WDM to boost data capacity. This marked the start of optical networking, as WDM became the technology of choice for expanding the bandwidth of fiber-optic systems.
  • 2009: The term software-defined networking (SDN) was first coined in an MIT review article
  • Present: 5G started becoming available in 2020.
    • Research and development for photonic technologies continues. Photonics solutions have more dependable laser capabilities and can transfer light at historic speeds, letting device manufacturers unlock broader applications and prepare next-generation products.

Trends in optical networking

Trends in optical networking, such as 5G integration, elastic optical networks, optical network security, interconnects in data centers, and green networking highlight the ongoing evolution of the technology to meet the demands of new technologies and applications.

5G integration

Optical networking enables the necessary high-speed, low-latency connections to handle the data demands of 5G applications. 5G integration makes sure that you get fast and reliable connectivity for activities such as streaming, gaming, and emerging technologies like augmented reality (AR) and virtual reality (VR).

Coherent optics advancements

Ongoing advancements in coherent optics technology contribute to higher data rates, longer transmission distances, and increased capacity over optical networks. This is vital for accommodating the growing volume of data traffic and supporting applications that need high bandwidth.

Edge computing

Integration of optical networking with edge computing reduces latency and elevates the performance of applications and services that call for real-time processing. This is imperative for apps and services needing real-time responsiveness, such as autonomous vehicles, remote medical procedures, and industrial automation.

Software-defined networking (SDN) and network function virtualization (NFV)

Adopting SDN and NFV in optical networking leads to better flexibility, scalability, and effective resource use. This lets operators dynamically allocate resources, optimize network performance, and respond quickly to changing demands, improving overall network efficiency.

Elastic optical networks

Elastic optical networks allow for dynamic adjustments to the spectrum and capacity of optical channels based on traffic demands. This promotes optimal resource use and minimizes the risk of congestion during peak usage periods.

Optical network security

Focusing on bolstering the security of optical networks, including encryption techniques, is important for protecting sensitive data and communications. As cyberthreats become more sophisticated, safeguarding your networks becomes paramount, especially when transmitting sensitive information.

Optical interconnects in data centers

The growing demand for high-speed optical interconnects in data centers is driven by the requirements of cloud computing, big data processing, and artificial intelligence applications. Optical interconnects have the bandwidth to handle large volumes of data within data center environments.

Green networking

Efforts to make optical networks more energy-efficient and environmentally-friendly align with broader sustainability goals. Green networking practices play a key role in decreasing the environmental impact of telecommunications infrastructure, making it more sustainable in the long run.

Bottom line: Optical networking is here to stay

The progression of optical networking has been instrumental in shaping the history of computer networking. As the need for faster data transmission methods grew with the development of computer networks, optical networking provided a solution. By using light for data transmission, this technology enabled the creation of high-speed networks that we use today.

As it grows, optical networking is doing more than just providing faster internet speeds. Optical network security, for instance, can defend your organization against emerging cyberthreats, while trends like green networking can make your telecommunication infrastructure more sustainable over time.

Read our guide on top optical networking companies and get to know the leading optical networking solutions you can consider for your business.

Liz Laurente-Ticong
Liz Laurente-Ticong
Liz Laurente-Ticong is a tech specialist and multi-niche writer with a decade of experience covering software and technology topics and news. Her work has appeared in TechnologyAdvice.com as well as ghostwritten for a variety of international clients. When not writing, you can find Liz reading and watching historical and investigative documentaries. She is based in the Philippines.

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