Understanding Optical Fiber: The Backbone of Modern Communication

Optic fiber has formed the basis for contemporary communication networks, emerging in the age where real-time interaction and fast data sharing are the norms. This transformative technology uses light waves to transmit enormous amounts of information over huge distances quickly and efficiently. But what is its working mechanism, and how has it come to power the internet, telecommunications, and even essential infrastructures? This article will attempt to explain the science backing optical fiber, its merits over copper-based systems, and its critical importance in determining the future of the digital world. Whether you are a technology buff, a professional in the industry, or merely inquisitive about the systems that interlink our world, this article will try to simplify the science of optical fiber technology while underscoring its role as the pivot of modern communication networks.

What is Optical Fiber and How Does it Work?

Optical fiber technology consists of a glass and plastic strand, termed as fiber strands, through which data can be transmitted as light pulses. Each fiber strand is almost a human hair thick, containing three primary components: core, cladding and a protective coating. The core, which is the inner portion, is light’s medium and is surrounded by the clad which reflects light back into the core through total internal reflection. Such a structure permits minimal transmission loss over large distances.

A transmitter is responsible for transforming electric signals into light, which then travels through the optical fiber. At the opposite end, light is transformed into electric signals and is processed. Optical fibers have very little interference and are ideal for high-speed data transmission. They are used for internet communication, cable TV and telecommunication.

Definition of Optical Fiber

Flexible strands of glass or plastic, known as optical fibers, are made to convey light signals over extensive distances while maintaining signal quality. Due to its effectiveness and resistance to electromagnetic interference, it is extensively employed in high-speed communication applications such as Internet services, telephone networks, and cable television.

How Optical Fiber Transmits Data

An optical fiber uses a laser or LED to generate pulses of light for data transmission. These light pulses signify binary strings to be communicated, serving the purpose of forming the basis of digital communication. An optical fiber is composed of purged glass or plastic and has a core through which light passes. In order to avert signal leakage, reflective cladding encasements are placed around the core.

The procedure of transmitting data starts when an electrical signal is transformed into a light signal by an optical transmitter. The signal is sent via the fiber core where total internal reflection occurs which largely mitigates signal loss as the light hits the inner walls of the cladding. Optical amplifiers placed on the fiber cable are capable of boosting weakened light signals over long distances. This allows transmission rates of becoming several terabits per seconds over long distances.

Some of the latest innovations that incorporate modern technologies are wavelength division multiplexing or WDM. WDM multiplexes signals at different wavelengths and coupled with single mode fibers, data is forecasted to transmit hundreds of kilometers without signal loss washing away the unparalleled limits of bandwidths.

Fiber optic technology is critical in addressing the ever-growing worldwide demands for quick data transfer and dependable, secure access within extensive networks.

Key Components of Optical Fiber

Like other light transmission devices, optical fibers consist of many components, some of which allow them to perform the light signal transmission at long distances without considerable loss of the light signal. The components of optical fibers and their functions are described below.

Core

The core is the inner segment of an optical fiber responsible for light conduction. Spirally wound ultra-pure glass or plastic is used for its formation, and its diameter depends on the type of fiber. Single-mode fibers have a core diameter of about 8-10 microns, while multimode fibers have comparatively broader cores of 50-62.5 microns. Signal quality and the level of attenuation within a transmission over a distance is directly affected by the core purity and composition and, therefore, must be optimal.

Cladding

The part of the optical fiber that caps its core is called as cladding, and its composition has a lower refractive index in comparison to the core. Due to this difference, every time a light signal exits the core for the fiber, it leads to total internal reflection. This makes light signal to remain in the core to travel through out the fiber. Signal strength and fiber dispersion are greatly reduced due to the cladding, which serves these functions.

Buffer Coating

The buffer coating is the protective layer that encompasses the optical fiber at the cladding region. It is primarily of plastic or some polymer type to prevent physically and environmentally caused damage as well as protect against moisture. With buffer coating, the optical fiber becomes more reliable and long-lasting.

Strengthening Members

These parts contribute to the mechanical reinforcement and limit the chances of fiber breakage while handling or installing the fiber. Usually made of aramid yarn or kevlar, fiberglass or strengthening members contribute to the tensile strength of the cable without compromising on flexibility.

Outer Jacket

The protective covering of the fiber construction called the sheath or outer jacket covers the outer part of the entire fiber construction. It is made of tough materials like polyethylene and PVC, which guard against external mechanical factors like impacts and abrasion. In particularly sensitive industrial environments, the outer jacket is additionally equipped with shielding to protect from electrical interference.

Optical Connectors

For instrumentation or networking devices, optical connectors are one of the most crucial accessories used to connect the optical fibers. For particular purposes, SC, ST, LC, and MTP/MPO connectors are used as the most common ones. Losses in signal when connecting and disconnecting using high-quality connectors are minimal compared to using low-grade connectors.

These elements together allow optical fibers to manage data transmissions with terabit levels at high signal integrity. Continuous improvement of advanced manufacturing technologies and materials, contributes to the widespread utilization of fiber optics in telecommunications, data centers, and IoT networks around the world. For example, recent developments of bend insensitive fibers, which are less likely to suffer performance loss when tightly bent, expand the use cases of optical fibers in confined spaces.

What are the Types of Optical Fiber?

Single-mode Optical Fiber Explained

Like all fiber optic cables, A single-mode optical fiber is designed to carry and transmit light signals over longer distances with minimal signal loss. While carrying one mode of light, single fiber reduces modal dispersion which makes it more efficient for long-distance, high precision communication. Single-mode fibers are ideal for long intercontinental telecommunications links and for metropolitan area networks (MANs).

Single-mode fibers allow data or signals to be transmitted more than 40 km without amplifying the signal. Single-mode fibers also tend to be more efficient when paired with wavelength-division multiplexing technologies. Single-mode fibers can reach data transmission rates greater than 100 Gbps, meaning modern, high-speed networks can rely on it. This capability is crucial as global data traffic continues to rise due to applications such as streaming services, cloud computing, and 5G deployment.

Other distinguishing features of single-mode optical fibers are their lower attenuation rates, usually below 0.20 dB/km at 1550 nm wavelengths, and exceptional reliability in preserving signals over long distances. These reasons make single-mode fibers the go-to option for enterprises and service providers needing strong, expandable, and advanced-ready communication systems. Its remarkable performance makes it a supporting technology in network infrastructure around the world.

Understanding Multimode Optical Fiber

The multimode optical fiber facilitates communication over shorter distances, which is why it is often used in local area networks (LANs), data centers, and intra-building networks. It contains a larger core diameter than single-mode fiber, enabling it to propagate multiple light modes simultaneously. However, increased modal dispersion occurring from the simultaneous propagation of light signals makes it difficult for signals to travel long distances. This type of fiber is effectively used in applications that require limited distance transmission due to the use of LEDs, which are less expensive than lazer diodes, making it an economical choice.

Comparing Optical Fiber and Copper Cable

Due to its application, copper cables and optical fibers differ in terms of speed, bandwidth, interoperability, durability, and cost. Copper cables are surpassed by optical fibers when it comes to data transfer speed. Optical fibers can go as high as 100 Gbps compared to copper cables. In the modern day, high-speed internet, video streaming, and cloud computing require massive amounts of data, and fiber cable bandwidth capacity supports it.

When used over short distances, copper cables tend to be more economical. However, they are prone to signal interference or electromagnetic emitted radiation (EMI). Unlike copper cables, which can easily face such issues, optical fibers are immune to wires as they send data in the form of light rather than electrical signals. Therefore, they can be used in places with heavy electrical activity like medical or industrial settings.

Despite their differences, optical fibers and copper cables have one feature in common: the difference in durability. Fiber optic cables are made of glass or plastic, meaning they are highly resistant to corrosion and no other damage, making them lightweight. In terms of handling, they have to be taken under strict supervision. For physical handling, copper cables are easy to deal with, however, their long term performance is heavily impacted due to moisture and oxidation which slowly degrades them.

At first, copper cables are less expensive and simpler to install, especially in the case of smaller networks or short-distance applications. However, Fiber optic cables outperform other types of cables in cases of high-performance systems because they have low attenuation rates and are capable of meeting the market’s growing demand for data-intensive operations over longer distances. Although the installation costs of optical fibers are higher than those of copper cables, advancements in technology and growing usage are continuously reducing the costs of installation, making it more accessible for private and commercial use.

What are the Advantages of Optical Fiber?

High-Speed Data Transmission

The backbone of modern communication networks, Optical fiber technology, has become unrivaled in data transmission speed. Capacities of only a few terabits per second copper cables can not compete with the glass used in optical fibers. Fibers transmit data with the use of light signals that are capable of traveling long distances with minimal interference or signal degradation.

Users are often provided with speeds of 1 Gbps or more optical fiber broadband services, depending on the infrastructure and service provider. More recently, advancements in Dense Wavelength Division Multiplexing (DWDM) technology allow for even greater data capacities to be achieved with optical fibers by allowing the transmission of multiple data streams simultaneously through different light wavelengths, which drastically increases efficiency on already capable optical fibers. This ruggedness, combined with extreme speed, makes optical fibers essential for cloud computing, video conferencing, and cloud computing applications.

Security Benefits of Optical Fiber

The use of fiber optics instead of copper wiring increases the level of security within the telecommunications infrastructure. As the data transfers over fibers, the light waves carrying the information are not subject to electromagnetic interference and cannot be intercepted easily since they remain confined within the core of the fiber. There is little to no chance of interception, making it a much safer method of data transmission.

Due to the restrictions posed by optics threads, detecting when an optical threading wire is tapped remains tremendously difficult. While copper cables have I interceptable signals, taking advantage of optical fibers requires precise physical access. Any type of intrusion tends to lead to a considerable level of signal drop or degradation, causing alert systems to signal the breaching of security protocols.

Optical fibers offer a greater degree of safeguard for confidential information with the flawless integration of encryption systems over the network. Recent analyses emphasize the importance of quantum key distribution (QKD) in optical fiber systems, claiming unbreakable encryption harnessing the energy of quantum physics.

The robustness and dependability of optical fibers further improve data security. These cables have a minimal risk of suffering physical damage, as well as environmental damage, reducing vulnerabilities significantly. An analysis done in the year 2021 showed that more than eighty percent of enterprises recognized optical fibers to be their preferred data safeguarding tool, attributing this preference to its robust security against data manipulation and enhanced data integrity during transfer.

With the addition of these attributes, optical fiber holds the potential to be a STEALTH solution for sectors that have confidential data, such as healthcare, financial services, and government operations.

Durability and Longevity of Fiber Optics

Designed for remarkable robustness and lifespan, fiber optic cables are suitable for long-term infrastructure projects. The glass or plastic core of fiber optics is sheathed in a soft covering, which allows the cables to endure harsh environmental factors such as extreme temperatures, moisture, and prolonged exposure to UV radiation. Research indicates that if installed properly with minimal upkeep, fiber optic cables outperform traditional copper cables by outlasting them in service life—using them for over 25 years hinges solely on the installation conditions and maintenance efforts.

Fiber optics are also well-known for their strong resistance to electromagnetic interference (EMI), allowing them to maintain stable functionality even in highly electronic environments. Other research documented insufficient exposure to degradation over time, further reducing the need for repetitive maintenance. All of these features combined elevate fiber optic systems to leaders in cost efficiency and sustainability across telecommunications, energy, and transportation industries that rely on long-lasting infrastructure.

How is Optical Fiber Used in Fiber Optic Networks?

Role of Optical Fiber in Internet Infrastructure

Optical fibers represent the underpinning of the internet infrastructure as they support the swift and trustworthy transmission of data over long distances. In my view, its strongest attributes, like its remarkable bandwidth and dampened signal loss issues, are crucial in managing data traffic that is generated all around the world. The heart of transcontinental connections is fiber optics located in undersea cables, which provides exceptional speed, low latency and helps local networks while simultaneously connecting continents and maintaining global connectivity. Such advancement in technology meets the requirements of growing demands and increases efficiency provided in the use of the internet.

Applications in Telecommunications

The efficiency and reliability of fiber optic technology have positioned it as a mainstay in modern telecommunication systems. Find below the most important uses of this technology.

Internet Backbone Infrastructure

The internet’s structural framework relies heavily on fiber-optic cables, which are capable of transferring data over extensive distances. These cables can also self-adjust to handle changes in worldwide internet traffic without causing delays or loss of accessibility.

Submarine Communication Cables

Fiber-optic cables ran under the ocean link continents together. These cables are important for international data exchange since they can carry hundreds of terabits of data per second and allow global convergence.

Telephone Networks

Due to the effectiveness of transmitting voice and data signals over optical fibers, the landline and cellphone networks use these cables for their telephone systems. Optical fibers guarantee exceptional intercellular communication thanks to low noise levels and minimal downtimes.

Cable Television (CATV)

CATV makes use of fiber optics for recording and broadcasting high-definition television because a single fiber can transport tremendous amount of data, in addition to multiple channels without interference.

5G Networks and Mobile Connectivity

5G infrastructure depends on fiber optic technology because it allows for fast and efficient connections between cell towers and its core networks, which, in turn, increases the speed and number of connected devices.

Enterprise Networking

Companies use fiber optics to maintain a private network with secure and high-speed data transmission in support of cloud computing, video conferencing, and large-scale data transfers.

Data Centers

In data centers, fiber optic cables are crucial due to their high-speed connectivity and capacity to transfer large amounts of data between servers and storage devices with lower power consumption.

Defense and Aerospace Communication

The military and aerospace sectors use fiber optics to enable secure and fast communication. Additionally, fiber optics are light and durable, making them useful in harsh environments.

Healthcare Systems

Medical data and imaging between hospitals, clinics, and laboratories are transmitted via fiber optics quickly and securely to enable timely care and efficient system throughput.

Remote Work and Learning

With an increase in remote activities, fiber optics offer the needed bandwidth for uninterrupted high-speed video calls, streaming, and file sharing, thus catering to the high demand for reliable virtual connectivity.

Integration with Optical Network Systems

The fusion of fiber optics with complex optical networks has transformed data transmission capabilities with a high-capacity, low-latency solution to meet the requirements of the global marketplace. For example, with Dense Wavelength Division Multiplexing (DWDM) technology, multiple data signals are transmitted through a single optical fiber at the same time using different light wavelengths. This increases the scalability of networks because it supports up to sixty-four channels per fiber and enables over 1 Tbps of data transfer.

Optical network systems use sophisticated and modern technology such as Reconfigurable Optical Add-Drop Multiplexers (ROADMs), which add a new level of flexibility and automation to network management. These systems provide the capability to change the configuration of the wavelength dynamically used in different areas of the network to optimize the flow of traffic and give priority to data that is critical, minimize downtime, and reduce operational costs. In addition, new technologies in photonic integration are creating large opportunities for miniaturized low-power systems, which makes them greener in terms of infrastructure.

Reports indicate that the global optical networking market is growing significantly, is estimated to be about $37 billion by 2028 at a CAGR of over 8.3%. Growth stems from the expanding use in sectors such as telecommunication and financial services that depend on secure and reliable high-speed networks. Such integration of fiber optics with optical network systems enables current-day connectivity as well as future technologies like 5G and the Internet of Things (IoT).

What are the Types of Fiber Optic Cable?

Indoor vs. Outdoor Fiber Optic Cables

Outdoor and indoor fiber optic cables: Like every other fiber optic cable, they are designed to serve specific performance requirements that suit the environment they are installed in for both durability and performance.

Indoor cables: Indoor cables are specifically designed to be utilized indoors, within a controlled environment. This means that such cables are usually low-profile and much easier to install in buildings like data centers or in wall conduits. Due to the installation requirements of most buildings, these cables are usually constructed using tight-buffered designs, which are much more flexible and resilient to handling during installation. OFNR (Optical Fiber Nonconductive Riser) and OFNP (Optical Fiber Nonconductive Plenum) rated flame-retardant jackets are used to satisfy the stringent fire safety requirements enforced by the building codes. Indoor cables are better suited for shorter runs (usually less than 300 feet for indoor cables used to connect routers, switchers, and other network devices).

Outdoor Fiber Optic Cables: As with any outdoor cabling system, these cables are designed to withstand more severe exposure to different external conditions. Outdoor cables have protective layers that include water-blocking, UV-resistant jackets, and in some cases, added armor to protect against physical damage, moisture, rodents, etc. Loose-tube construction is also common in these cables, where the fibers are kept in a tube filled with gel that protects them from extreme temperatures and water. These cables are usually used to transmit data over long distances and for external connections between buildings. Industry research suggests that outdoor fiber optic cables are vital for supporting large metropolitan networks and can stretch for distances of several miles.

Based on the use case deployment scenario, the appropriate cable type may be chosen. While indoor cables are tailored to provide flexibility and safety, outdoor cables are designed with durability and resistance against the elements in mind. For more complex infrastructures, hybrid indoor and outdoor solutions are increasingly used to better perform under varying conditions.

Armored Fiber Optic Cable Features

The design of armored fiber optic cables considers high levels of protection and dependability in challenging application areas.

These cables have a protective covering, which might be metallic or non-metallic, providing them with a strong construction and protecting the optical fibers from mechanical stresses, crushing, and external impacts. Below are some of the features and technical aspects regarding armored fiber optic cables:

Improved Longevity

As a result of the stresses caused by tension, abrasion, or deformation, these cables don’t incur damages. Steel or Aluminum tend to be the metal used for the armor and even increase the mechanical protection. It is ensured therefore that the fibers can endure extremely high external pressure, typically anywhere from 2,000 newtons (N) or more, depending on the model and manufacturer.

Resistance to Environmental Factors

Outdoor applications are sometimes inflicted with harsh environmental conditions under which these cables are engineered to operate. They can withstand a range of temperatures, moisture, UV radiations, and even chemicals. Because of the robust jackets and armored layers, the cables can be used for subterranean, underwater, or even industrial drills.

Pest and Rodent Protection

These cables have armor which are made using metal and protects the sheath from abrasion and cuts and becomes a common problem for many installations. The chances of these scenarios happening in areas infested with rodents greatly decreases with the use of these cables.

Advancement for long distance communication

The armored cables containing fiber optic features help in carrying data from one place to another over large distances without signal loss. The cables use single-mode fibers, which allows for high-speed data transfer, communication, and reception (telecommunication) at low latency and with large bandwidth for high distance (more than 10 km).

Safety compliance with regards to fire hazards

Armored fiber optic cables can be fire retardant and comply to various fire safety standards like IEC 60332 or UL 1666 specifications. As a result, the performance reliability in a setting that poses fire risks or is bound to strict safety codes is guaranteed.

Core Configurations: Multiple at once

The network conformation is galvanized with the armored cables which come in various core counts of two or even more than 144 fibers. The multi core settings are most suited for large scale data centers or even industrial telecommunication networks.

Application use flexibility

The flexible rough cable jacket allows the armored cables to be used in a broad selection of applications from aerial garnets to underground and transitions between indoor and outdoor. Such versatility helps in deployment across a range of circumstances.

Armored fiber optic cables contain all of these features, which leads to unmatenced efficient performance and reliability in the most challenging environments.

Understanding Fiber Optic Cable Construction

Fiber optic cables are intricate assemblies that are capable of light signal transmission over extensive distances with high strength, speed, and durability. The various essential parts of a fiber optic cable are:

• Core: The light signals are carried by the core, the innermost part of the fiber optic cable. It is made of pure glass or plastic to ensure minimal signal loss. Core diameter differs based on the cable type, with single mode cables having a smaller core size of 8-10 microns and multi-mode cables having a larger core of 50-62.5 microns.
• Cladding: The cladding is a glass or plastic covering of the core with a lower refractive index, enabling it to focus reflection light through the core. This allows for avoidance of signal loss through total internal reflection.
• Buffer Coating: This coating offers protection from water, physical damage, and stress from the environment. Typically, these coatings are made of acrylate or polymer materials, but stronger substances are utilized in rough environments.
• Strengthening Members: Fiber optic cables are made stronger through baking steel wires, fiberglass, and aramid yarn such as Kevlar. Alongside these materials provide tensile strength, which guards the cable from breaking and stretching during installation or operation.
• Jacket External: The outer layer serves as the primary protection for the cable from abrasion, chemical exposure, and temperature changes. To achieve the intended operational environment, the jacket is frequently constructed from polyethylene, polyvinyl chloride(PVC), or low smoke zero halogen(LSZH) materials.

Optional Additional Protective Coating: Some fiber optic cables come with additional protective tape shielding like aluminum or steel shielding to defend against electromagnetic interference (EMI) or physical damage.

Important Facts On The Value Of Fiber Optic Cables

• The efficiency and performance of cables have undergone improvement in recent years. For example;
• With minimal data attenuation, modern fiber cores transmit data at speeds greater than 10 Gbps over distances of more than 40 kilometers.
• The high density polyethylene outer jackets are ideal for extreme environmental conditions since they can endure temperatures ranging from 176°F to -40° (or -40°C to 80°C).
• Multimode optical fibers with optimized index of refraction profiles achieve low modal spectral dispersion supporting high-broadband data center and local area network (LAN) applications.

All the elements set forth, alongside the design parameters and metrics, demonstrate the reliability of fiber optic cables supporting world communication networks alongside advanced technologies.

Frequently Asked Questions (FAQs)

Q: What is optical fiber technology, and how does it work?

A: Optical fiber technology utilizes flexible transparent glass or plastic fibers to transfer data through light signals. Fiber optics utilizes the principle of total internal reflection, which keeps light traveling along the length of the fiber while its core efficiently carries the optical signal over long distances.

Q: What are the main types of optical fiber cables?

A: There are two main types of optical fiber cables: single-mode fiber and multimode fiber. Single-mode fiber is utilized for long-distance communication as it allows light to travel straight down the fiber. Multimode fiber is useful for shorter distances as it supports multiple light paths or modes.

Q: What components make up an optical fiber cable?

A: An optical fiber cable comprises several fundamental components: the core that houses the signaling light, the cladding that reflects light into the core, and the protective outer jacket. Some cables also include members of strength and buffering, which are meant to defend against physical damage.

Q: Explain how a fiber optic sensor operates.

A: A fiber optic sensor operates by measuring the changes in light which may happen in intensity, phase, polarization, or wavelength as it travels through the fiber. A sensor can now measure temperature, pressure, and strain with very high accuracy.

Q: What are the benefits of using fiber optic cables as opposed to copper cables?

A: Fiber optic cables have higher bandwidth, longer distances between transmission points without signal alteration, and are not affected by electromagnetic interference, among other advantages, when compared to copper cables. Fibers are also lighter, smaller, and more data-efficient than copper cables.

Q: In what ways is optical fiber used in advanced technology?

A: Aside from its use in telecommunications and data internet networks, optical fibers are useful in medicine for imaging, in industrial monitoring, and in military and aerospace applications. Optical fibers are even used in the development of fiber lasers, making them extremely versatile.

Q: How does multimode fiber differ from single-mode fiber?

A: With multimode fiber, more than one light path can travel through the fiber due to the larger core diameter. This allows the mode to be suited for shorter distance applications. Single-mode fiber, on the other hand, has a smaller core, which makes it ideal for long-distance communication.

Q: What is the importance of fiber optic sensors in industrial purposes?

A: Fiber optic sensors are extremely important for industrial purposes as they give exact measurements of a certain physical parameter, which can include temperature, pressure, or even strain. Fiber optic sensors are appreciated because they can survive harsh conditions and do not respond to electromagnetic interference.

Q: What is a fiber laser, and what can it be used for?

A: Fiber lasers are a type of laser where the active gain medium is an optical fiber doped with rare earth elements. Because of their high efficiency and compact size, fiber lasers have found applications in processing materials and telecommunication and are even used in medical procedures.

Reference Sources

1. Optical Fiber Sensors and Sensing Networks: Overview of the Basic Concepts and Principles (Pendão & Silva, 2022)

• Publication date: 2022.
• Methodology: Literature review.
• Key Findings: In this review article, the authors delineate the main features of optical fiber sensors and sensing networks (OFSNs), analyzing their merits (dimensions, weight, high-temperature and pressure resistance, electromagnetic passivity) and various uses (long distance or remote monitoring, dangerous environments, health care monitoring). It covers the incorporation of OFSNs into Wireless Sensor Networks (WSN) as well.

2. The principles of physics and the uses of Raman-distributed optical fiber sensing technology (Li & Zhang, 2022)

• Publication Date: 2022
• Methodology: Review of other scholars’ literature.
• Key Findings: In this case, the authors focus on the Raman distributed optical fiber sensing as a method of measuring temperatures of a distributed system. The review is oriented around finding four theoretical/technical bottlenecks on traditional Raman sensing (Raman optical attenuation, weak signal-to-noise ratio, distance versus resolution, lack of dual-parameter detection) and analyzing its performance and application advancements.

3. Immunosensing Based on Optical Fiber Technology: Recent Advances (Soares et al., 2021)

• Publication Date: 2021
• Methodology: Integrated methodologies.
• Key Findings: The authors focus on the configurations of immunosensor systems describing various types of optical fiber: uncladded, U-shape, D-shape, tapered, etc. Along with biosensing, they describe fiber biofunctionalization using evanescent waves, surface plasmon resonance, localized SPR, and more. The review showcases the recent progress and applications of biosensing technologies.

4. Optical fiber

5. Single-mode optical fiber

6. Computer network