2. content
• Abstract
•Elements of SDM-WDM optical networks
•Terrestrial Networks
•Under sea system
•Network supporting 5G/6G wireless access
•Data center interconnects and networks
• Conclusion
• Reference
3. Abstract
Compared with the large range of optical switching technologies that have been the subject of research, very few have been deployed on a significant scale in
telecommunications networks. From an industrial and commercial viewpoint, this paper describes the current status of the more successful ones and relates
them to their network applications and to possible future developments in optical switching
4. Elements of SDM-WDM optical networks
A. OPTICAL FIBRE
Optical fiber technology has revolutionized the telecommunications industry by enabling the transmission of vast amounts of data
over long distances at high speeds. However, with the ever-increasing demand for data and the limitations of electronic switching
technologies, there is a growing need for more efficient and faster optical switching technologies to manage the flow of data in fiber-
optic networks.One promising approach to optical switching is to exploit the spectral and spatial degrees of freedom of light in optical
fibers. Spectral switching involves selectively routing different wavelength channels to different output ports, while spatial switching
involves routing the light to different locations within a fiber.
5. B. OPTICAL SWITCHES
Wireless USB .Optical networks are composed of fiber links connectinggeographically distributed sites where switching nodes
aredisposed. In today’s WDM-based networks, carried overSMF, the switching functionality is called ROADM node.ROADM nodes
employ multiple 1 × N-port WSSs in aroute-and-select topology [29], where N is the output portcount (a distributing WSS on each
ingress fiber and acombining WSS on egress fibers combine for a Spanke-topology architecture [30] per wavelength). Internally,WSS
spatially disperses the input fiber spectrum for access-ing the optical bandwidth of each WDM channel and beam-steer each
wavelength channel to the desired output port(out of N) using a pixelated SLM. Using an SLM enablesthe WDM channel spacings and
bandwidths to be software-defined (and in-field modified, i.e., flexible-grid property making them future-proof as higher baud rate
trans-mission rates and new WDM channel plans emerge, but theSLM switching technology is relatively slow WSS variants based on
WDM channel demultiplex-ers followed by discrete space switches do not supportflexible grid operation but allow the introduction of
fasterswitching technologies, e.g., microsecond and nanosecondswitching times [32], [33]. This demonstrates how differ-ent features
of an implemented switch can be leveraged for diverging networking requirements.
6. C. SPACE DIVISION
Space-division demultiplexers (also known as spatial demultiplexers or simply DEMUX) are devices used to separate the signals that
have been combined by a space-division multiplexer. These devices separate the signals and route them to their respective
destinations.
Fan-in devices are used to combine multiple input signals into a single output signal. These devices are commonly used in electronic
circuits to merge multiple signals, such as audio or video signals.
7. D. OPTICAL AMPLIFIER
Optical amplifiers are devices that amplify optical signals without converting them into electrical signals. They are used to boost the
strength of an optical signal, allowing it to travel over longer distances or through more optical components without significant
degradation. Optical amplifiers are important components in optical communication systems and have replaced traditional
electronic repeaters in many applications.
8. E. OPTICAL TRANSCEIVERS
There Optical transceivers are devices used in fiber-optic communication networks to transmit and receive optical signals. They are
essentially the interface between the optical fiber and the electronic devices that process the information being transmitted.
An optical transceiver typically consists of a transmitter and a receiver. The transmitter converts electrical signals into optical signals
and sends them over the fiber-optic cable. The receiver then receives the optical signals and converts them back into electrical
signals that can be processed by electronic devices.
9. Terrestrial Networks
TheTerrestrial networks are communication networks that use land-based infrastructure to transmit and receive data. These
networks can be wired or wireless and are used for various applications, such as telecommunications, broadcasting, and internet
connectivity.
Wired terrestrial networks include copper-based networks, such as digital subscriber line (DSL) and cable networks, and fiber-optic
networks. DSL and cable networks use existing copper-based infrastructure to provide high-speed internet access to homes and
businesses. Fiber-optic networks, on the other hand, use optical fibers to transmit data over long distances at high speeds.
10. Under Sea System
Undersea fiber-optic communication systems have become a critical component of the global telecommunications infrastructure, facilitating international
communications, commerce, and information exchange. As such, there is a growing need for more efficient and reliable optical switching technologies that can
manage the flow of data in these complex networks.
The use of spectral and spatial degrees of freedom in optical switching can have several benefits for undersea fiber-optic communication systems. Spectral
switching can enable the multiplexing of multiple wavelength channels onto a single fiber, increasing the amount of data that can be transmitted over the same
physical infrastructure. Spatial switching, on the other hand, can be used to route the light through multiple fibers, allowing for more efficient network
reconfiguration and fault tolerance.One of the main challenges in undersea fiber-optic communication systems is the high attenuation and dispersion of light
over long distances. This can lead to signal degradation and the need for expensive signal regeneration and amplification technologies. However, the use of
spectral switching can enable the selective amplification of specific wavelength channels, reducing the need for costly signal regeneration.
11. Network Supporting 5G/6G Wireless Access
5G and 6G wireless access networks are expected to provide unprecedented levels of connectivity and enable new applications and
services that require high-bandwidth, low-latency, and high-reliability communication. To support these advanced wireless access
networks, several new technologies and network architectures are being developed.
One of the key technologies being developed to support 5G and 6G wireless access networks is network slicing. Network slicing
allows for the creation of virtualized network functions that can be customized and optimized for specific applications and services.
This can enable more efficient use of network resources, improve network performance, and enable the creation of new services that
require specialized network capabilities.
12. Data Center Interconnectes And Networks
Data center interconnects (DCIs) are high-speed network connections that connect two or more data centers, allowing them to share
resources, data, and applications. DCIs are essential for modern enterprise IT infrastructures that rely on distributed applications
and cloud computing services.The architecture of DCIs has evolved over time, from simple point-to-point connections to more
complex mesh networks. Today, DCIs are typically implemented using high-speed optical fiber networks that can support high data
rates and low latencies.
13. Conclusion
Societal intake of information has been rising exponentially for decades and will continue to do so for the foreseeable future. Serving
this demand and scaling the transported capacity across all communication forms in a technology and cost-effective manner is a
constant challenge the research community faces. As technology innova-tions are introduced into communication systems, demand
is initially easily satisfied, but as it is rising exponentially,eventually inherent limits are reached. This is currently the state of affairs
in fiber-optic communications, where the capacity limits of SMF are well understood and rapidlyapproaching.
