What is optical networking? Full explanation

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

This technology supports the transmission of large amounts of data at high bandwidth, enabling faster and more efficient communications compared to traditional copper cable networks.

The main components of optical networks

The major components of a fiber optic network 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.

Fiber Optic Cable

Fiber optic cable is a high-capacity transmission medium made of glass or plastic called optical fibers.

These optical fibers transmit light signals over long distances with minimal signal loss and high data rates. The core of each optical fiber is surrounded by a cladding material that reflects the light signal back into the core for efficient transmission.

Compared with traditional copper cables, fiber optic cables have the advantages of anti-electromagnetic interference and reduced signal attenuation, and have been widely used in telecommunications and network applications.

Optical transmitter

An optical transmitter converts electrical signals into optical signals for transmission over a fiber optic cable. Its primary function is to modulate a light source, typically a laser diode or light emitting diode (LED), in response to an electrical signal representing data.

Optical Amplifier

Optical amplifiers are strategically placed on fiber optic networks to boost optical signals, maintaining signal strength over longer distances. The component compensates for signal attenuation and allows for distance signal transmission without the need for expensive and complex optical-to-electrical signal conversion.

The main types of optical amplifiers include:

• Erbium-doped fiber amplifier (EDFA): EDFA uses erbium-doped fiber. When exposed to light of a specific wavelength, the erbium ions in the fiber absorb and re-emit photons, thereby amplifying the optical signal. EDFA is typically used in the 1550nm range and is a key component for long-distance communications.
• Semiconductor Optical Amplifier (SOA): SOA amplifies optical signals through semiconductor materials. The input optical signal induces stimulated emission inside the semiconductor, resulting in signal improvement. SOA is specifically used in short-distance and access network scenarios.
• Raman amplifiers: Raman amplifiers use the Raman scattering effect in optical fibers. Pump light of a different wavelength interacts with the optical signal, transferring energy and enhancing it. This type of amplifier is versatile and can operate at a variety of wavelengths, including the commonly used 1550 nanometer range.

Optical receiver

At the receiving end of the optical link, an optical receiver converts the incoming optical signal back into an electrical signal.

Transceiver

A transceiver is a multifunctional device that combines the functions of an optical transmitter and receiver into a single unit, facilitating bidirectional communications over a fiber optic link. They convert 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 multiple data streams to be transmitted simultaneously on a single optical fiber. The basic principle of WDM is to use different wavelengths of light to carry independent data signals, supporting the increase of data capacity and the efficient use of the spectrum.

Widely used in long-haul and metropolitan optical networks, WDM provides a scalable, cost-effective solution to meet the growing demand for high-speed, large-capacity data transmission.

Optical Add-Subtract Multiplexer

Optical Add-Drop Multiplexers (OADMS) are a major component in WDM optical networks, providing the ability to selectively add (inject) or drop (extract) specific wavelength optical signals at network nodes. OADMS helps optimize data flow in the network.

Optical switches and routers

Optical switches and routers both contribute to the development of advanced optical networks, providing solutions for high-capacity, low-latency and scalable communication systems to meet the changing needs of modern data transmission.

Optical switches selectively route optical signals from one input port to one or more output ports. They are very important for establishing communication paths in 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 packets at the network layer based on the destination address. They operate in the optical domain, maintaining the integrity of the optical signal without converting it to electrical form.

Optical Cross Connect (OXCS)

Optical Cross Connect (OXC) enables reconfiguration of optical connections by selectively routing signals from input fibers to desired output fibers. By simplifying wavelength-specific routing and rapid reconfiguration, OXCS helps improve the flexibility and low-latency characteristics of advanced optical communication systems.

How optical networks work

The function of optical network is to use optical signals to transmit data through optical fiber cables to create a fast communication framework. The process includes optical signal generation, optical transmission, data encoding, optical propagation, signal reception and integration, and data processing.

Optical signal generation

Optical networks first convert data into light pulses. This conversion is usually achieved using a laser source to ensure successful representation of the information.

Optical Transmission

In this phase, the system sends pulses of light carrying data through a fiber-optic cable. The light propagates within the core of the cable and bounces off the surrounding cladding due to total internal reflection. This allows the light to travel great distances with minimal loss.

Data Encoding

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

Light Propagation

Light pulses travel through fiber optic cables, providing high-speed, reliable connections within a network. This allows important information to be transferred between locations more quickly and securely.

Signal reception and integration

At the receiving end of the network, light-sensing devices, such as photodiodes, detect incoming light signals. The photodiodes then convert these light pulses back into electrical signals, increasing the integration of optical networks.

Data processing

The electrical signal is further processed and interpreted by electronic devices. This stage includes decoding, error correction, and other operations necessary to ensure the accuracy of data transmission. The processed data is used in a variety of operations to support critical functions such as communication, collaboration, and data-driven decision making.

8 types of optical networks

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

1. Mesh Network

Optical mesh networks interconnect nodes through multiple fiber links. This provides redundancy and allows dynamic rerouting of traffic in the event of a link failure, enhancing the reliability of the network.

• Typical Applications: Typically used in large-scale mission-critical applications where network resiliency 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 delivers optical cables and signals to end users. It uses unpowered optical splitters to distribute the signal to multiple users, making it passive.

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

3. Free Space Optics (FSO)

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

• Typical applications: High-speed communications in environments where it is impractical or difficult to lay optical fiber, such as urban areas or for military purposes.

4. Wavelength Division Multiplexing (WDM)

WDM uses a different wavelength of light for each signal, thereby increasing data capacity. Subtypes of wavelength division multiplexing include coarse wavelength division multiplexing (CWDM) and dense wavelength division multiplexing (DWDM).

• Typical applications: CWDM is used for short-distance metropolitan area networks, and DWDM is used for long-distance, high-capacity communications.

5. Synchronous Optical Network (SONET)/Synchronous Digital Hierarchy (SDH)

SONET and SDH are standardized protocols for transmitting large amounts of data over long distances using fiber optic cables. SONET is more commonly used in North America, while SDH is used by the international industry.

• Typical applications: SONET and SDH are designed for high-speed, long-distance voice, data and video transmission. They provide a synchronous and reliable transport infrastructure for telecommunications infrastructure and carrier networks.

6. Optical Transport Network (OTN)

OTN transmits digital signals in the optical layer of the communication network. It has functions such as error detection, performance monitoring and fault management.

• Typical Applications: Used with WDM to maximize resiliency of long-distance transmission.

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 commercial premises to provide high-speed Internet access.

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

8. Optical Cross Connect (OXC)

OXC facilitates the exchange of optical signals without converting them into electrical signals.

• Typical applications: Mainly used by telecom operators for traffic management in large optical networks.

Use of Optical Networks Today

Today, many industries and fields are using optical networks for high-speed and efficient data transmission. These include telecommunications, healthcare, financial institutions, data centers, Internet service providers (ISPs), enterprise networks, 5G networks, video streaming services, and cloud computing.

telecommunications

Optical networks are the foundation of telephone and internet systems. Today, optical networks remain critical to telecommunications, connecting cell sites, ensuring high availability through dynamic traffic rerouting, and enabling high-speed broadband in metropolitan and long-haul networks.

Healthcare

For healthcare, optical networks ensure fast and secure transmission of medical data, speeding up remote diagnosis and telemedicine services.

Financial institutions

Financial institutions use this technology for fast, secure data transfer, which is essential for activities such as high-frequency trading and seamlessly connecting branch offices.

Data Center

Optical networks in data centers connect servers and storage units, providing high-bandwidth and low-latency infrastructure for reliable data communications.

Internet Service Providers

ISPs use optical networks to provide broadband services, using fiber-optic connections for faster access to the internet.

Enterprise Network

Large enterprises use internal optical networks to connect offices and data centers, maintaining high-speed and scalable communications within their infrastructure.

Mobile network (5G)

For 5G mobile networks, optical networks allow for increased data rates and low latency requirements. Fiber optic connections connect 5G cell sites to the core network, bringing bandwidth for a variety of applications.

Video streaming services

Optical networks can achieve smooth data transmission, providing high-quality video content through streaming platforms, resulting in a more positive viewing experience.

cloud computing

Cloud service providers rely on optical networks to connect data centers to deliver scalable, high-performance cloud services.

History of Optical Networking

The combined efforts of several optical networking companies and prominent individuals have greatly shaped the optical networking landscape as we know it today.

• 1792: French inventor Claude Chappe invents the light signal telegraph, one of the earliest optical communications systems.
• 1880: Alexander Graham Bell patents an optical telephone system. However, his first invention, the telephone, is considered more practical.
• 1965: German physicist Manfred Börner demonstrates the first working fiber-optic data transmission system at the Telefunken research laboratory in Ulm.
• 1966: Sir Charles K. Kao and George A. Hockham proposed that optical fiber made of ultra-pure glass could transmit signals over distances of several kilometers without complete loss of signal.
• 1977: General Telephone and Electronics tests and deploys the world's first commercial fiber-optic network for long-distance communications.
• 1988-1992: Emergence of the SONET/SDH standard.
• 1996: The first commercial 16-channel DWDM system is launched by Ciena.
• 1990s: Organizations begin using fiber optic cables to connect Ethernet switches and IP routers in corporate local area networks (LANs).

Rapidly expand optical networks to support the growing demands of the Internet boom.

Organizations began using optical amplification to reduce the need for repeaters, and more businesses implemented WDM to increase data capacity. This marked the beginning of optical networking, as WDM became the technology of choice for extending the bandwidth of fiber optic systems.

• 2000: The bursting of the Internet bubble led to the decline of the optical network industry.
• 2009: The term software-defined networking (SDN) is first coined in a review article from MIT.
• 2012: Network Function Virtualization (NFV) was first proposed at the OpenFlow World Conference by the European Telecommunications Standards Institute (ETSI), which is composed of service providers such as AT&T, China Mobile, British Telecom Group, and Deutsche Telekom.
• Current status: 5G will be available starting in 2020.

Research and development in photonic technology continues. Photonic solutions have more reliable laser capabilities and can transmit light at historic speeds, enabling device manufacturers to unlock a wider range of applications and prepare for the next generation of products.

Optical Network Development Trend

Optical network development trends such as 5G convergence, elastic optical networks, optical network security, data center interconnection, and green networking highlight the continuous evolution of optical network technology to meet the needs of new technologies and new applications.

5G Integration

Optical networks are able to provide high-speed, low-latency connections to meet the data demands of 5G applications. 5G integration ensures you get fast and reliable connections for activities such as streaming, gaming, and emerging technologies such as augmented reality (AR) and virtual reality (VR).

Advances in coherent optics

Continuous advances in coherent optics technology help achieve higher data rates, longer transmission distances, and increased capacity in optical networks. This is critical to accommodating growing data traffic and supporting applications that require high bandwidth.

Edge computing

The integration of optical networks with edge computing reduces latency and improves the performance of applications and services that require real-time processing. This is essential for applications and services that require real-time responses, such as self-driving cars, remote medical procedures, and industrial automation.

Software Defined Networking (SDN) and Network Function Virtualization (NFV)

The adoption of SDN and NFV in optical networks can achieve better flexibility, scalability, and efficient use of resources. This allows operators to dynamically allocate resources, optimize network performance, and quickly respond to changing demands, thereby improving overall network efficiency.

Elastic Optical Network

Elastic optical networks allow the spectrum and capacity of optical channels to be dynamically adjusted based on business needs. This promotes optimal use of resources and minimizes the risk of congestion during peak usage periods.

Optical Network Security

Focusing on strengthening the security of optical networks, including encryption technology, is important to protect sensitive data and communications. As cyber threats become more sophisticated, it becomes critical to protect their networks, especially when sensitive information is being transmitted.

Optical interconnects in data centers

The demands of cloud computing, big data processing, and artificial intelligence applications are driving the growing need for high-speed optical interconnects in data centers. Optical interconnects have the bandwidth to handle large amounts of data in a data center environment.

Green Network

Efforts to make optical networks more energy efficient and environmentally friendly fit in with broader sustainable development goals. Green network practices play a key role in reducing the environmental impact of telecommunications infrastructure, making it more sustainable in the long run.

Conclusion: Optical Networking is Here to Stay

The development of optical networks has played an important role in shaping the history of computer networks. As computer networks grew, the need for faster ways to transfer data grew, and optical networks provided a solution. By using light for data transmission, this technology enabled the high-speed networks used today to be built.

As fiber optic networks grow, they can do more than just provide faster internet speeds. For example, optical network security can protect organizations from emerging cyber threats, while trends such as green networks can make telecommunications infrastructure more sustainable over time.