OPTICAL FIBRES

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TAG: GS 3: SCIENCE AND TECHNOLOGY  

THE CONTEXT: Along with quantum optics, fibre optic communication stands on the cusp of a new era. So, in this article we will discuss the intricacies of fibre optic cables, their historical evolution, working principles, technological advancements, and their current and potential future applications.

Introduction to Optical Fibres:

• Optical fibres are slender glass strands used for transmitting data in the form of light pulses.
• They’re incredibly thin, almost resembling the diameter of a human hair.
• They are capable of carrying vast amounts of digital information over long distances.

Evolution and Development:

• Historical background:
  • It traces the historical timeline of light guidance and manipulation from Colladon’s demonstration of light’s narrow stream in water jets to the early use of thin glass rods in medicine and defense.
• Landmark moments:
  • The contributions of scientists like John Tyndall, Clarence Hansell, John Logie Baird, and the significant breakthroughs by Harold Hopkins, Narinder Singh Kapany, Lawrence E. Curtiss, and Theodore Maiman have been significant.

Working Principle of Optical Fibres:

• Nature of Light:
  • Light is an electromagnetic wave with a spectrum of frequencies, including visible light, X-rays, radio waves, and heat.
  • Optical fibres utilize the properties of light to transmit data.
• Total Internal Reflection (TIR):
  • When light passes from one medium to another, such as from glass to air, its path bends due to the change in the refractive index.
  • Refractive index refers to how fast light can travel in a medium.
  • Total Internal Reflection (TIR) is the phenomenon where light traveling within a material strikes the boundary with another material at an angle greater than the critical angle and is reflected back into the original material instead of refracting outwards.
• Light Propagation in Optical Fibres:
  • Optical fibres consist of thin cylindrical strands of glass with a diameter close to that of a human hair.
  • These fibres serve as the medium for transmitting information encoded as digital data.
  • When a beam of light (carrying encoded information) enters an optical fibre, it passes through the glass but experiences partial reflection at the boundary between the glass and air due to the differences in refractive index.
  • If the angle of incidence is within a certain range (greater than the critical angle), the light will be totally reflected back within the glass fibre.
  • This total internal reflection allows the light to propagate through the fibre over long distances without significant loss of optical power.
  • The information encoded in the form of electromagnetic waves travels within the glass walls, bouncing off the internal surfaces of the fibre, and traverses several kilometers while retaining the integrity of the signal.
• Components of Fibre Optic Communication:
  • A fibre optic communication system comprises three essential components:
    • Transmitter: Encodes information into optical signals (rapidly blinking light pulses representing zeros and ones).
    • Optical Fibre: Carries the encoded signal over long distances using the principles of total internal reflection.
    • Receiver: Decodes the transmitted optical signals, reproducing the original information.
  • Advantages of Optical Fibres:
    • Optical fibres enable high-speed data transmission rates, capable of carrying large volumes of information, such as text, images, videos, and voice calls, almost at the speed of light.
    • Unlike traditional communication mediums like radio or copper cables, optical fibres are less susceptible to external interferences such as lightning and weather conditions.

CURRENT AND FUTURE APPLICATIONS:

• Telecommunications:
  • Fiber optics are extensively used in modern communication networks for transmitting data, providing high-speed internet, and enabling phone calls.
• Medical Science:
  • Optical fibers are employed in endoscopy, illuminating surgical sites, and transmitting images for medical procedures.
• Laser Technology:
  • Fiber optics contribute to laser technology, used in various industries for cutting, welding, and medical procedures like laser eye surgery.
• Sensing Technology:
  • Optical fibers have applications in sensing systems, including environmental monitoring and industrial sensors.
• Quantum Technologies:
  • Integration of fiber optics with quantum technologies is expected to revolutionize secure communication and computing.
• Expanded Connectivity:
  • Further advancements may bring enhanced fiber optic networks into homes and rural areas, providing faster and more reliable internet access.
• Smart Cities and IoT:
  • Fiber optics could play a pivotal role in creating interconnected smart cities and powering the Internet of Things (IoT) for improved efficiency and connectivity.

IMPACT AND SIGNIFICANCE:

• Global Connectivity:
  • Fiber optic technology has connected the world, facilitating instant communication, information exchange, and global interconnectedness.
• Technological Advancements:
  • Its continuous development has led to faster data transmission, better signal quality, and more durable and efficient fiber optic cables.
• Scientific Contributions:
  • Scientists, engineers, and researchers’ contributions in developing fiber optics have significantly impacted modern communication systems and various technological fields.
• National and Economic Importance:
  • Governments recognize its strategic importance, as reflected in initiatives like India’s national mission on Quantum Technologies and Applications, which highlights the technology’s potential economic and scientific benefits.

SOURCE: https://www.thehindu.com/sci-tech/science/fibre-optic-cables-explained/article67579264.ece