Historical Development of Optical Fiber:
– Colladons light fountain demonstrated guiding of light by refraction in Paris in the early 1840s.
– John Tyndall included total internal reflection in his lectures in London in 1870.
– Viennese doctors used bent glass rods for internal illumination in the late 19th century.
– Image transmission through optical fibers shown by Bram van Heel in 1953.
– First working fiber-optic data transmission system demonstrated by Manfred Börner in 1965.
Manufacturing and Types of Optical Fibers:
– Glass optical fibers made by drawing, plastic fibers by drawing or extrusion.
– Multi-mode fibers have wider core diameter for short-distance communication.
– Single-mode fibers used for communication links longer than 1,050 meters.
– High-quality optical fibers manufactured at increasing speeds for cost-effectiveness.
Key Innovations in Optical Fiber Technology:
– Charles K. Kao and George A. Hockham proposed reducing fiber attenuation below 20 dB/km in 1965.
– Robert D. Maurer, Donald Keck, Peter C. Schultz, and Frank Zimar achieved 17 dB/km attenuation in 1970.
– General Electric produced fiber with 4 dB/km attenuation using germanium dioxide.
– Thomas Mensah increased fiber manufacture speed to over 50 meters per second.
– Photonic-crystal fiber developed in 1991 for improved guidance of light.
Partnerships, Deployments, and Applications:
– Corning and CSELT collaborated on practical optical fiber cables.
– First metropolitan fiber optic cable deployed in Turin in 1977.
– Erbium-doped fiber amplifier developed to reduce long-distance fiber system costs.
– Fiber optics applied in various fields like medicine and telecommunications.
– Telecommunication and computer networking applications.
Technical Aspects and Uses of Optical Fiber:
– Principle of Operation and Refractive Index in optical fibers.
– Total Internal Reflection and its role in confining light in the core.
– Multi-mode and Single-mode Fiber characteristics and applications.
– Attenuation mechanisms, factors affecting attenuation, and techniques to reduce it.
– Importance of attenuation in optical communication and effects on signal quality and data rates.
An optical fiber, or optical fibre, is a flexible glass or plastic fiber that can transmit light from one end to the other. Such fibers find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. Fibers are used instead of metal wires because signals travel along them with less loss and are immune to electromagnetic interference. Fibers are also used for illumination and imaging, and are often wrapped in bundles so they may be used to carry light into, or images out of confined spaces, as in the case of a fiberscope. Specially designed fibers are also used for a variety of other applications, such as fiber optic sensors and fiber lasers.
Glass optical fibers are typically made by drawing, while plastic fibers can be made either by drawing or by extrusion. Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction. Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide. Fibers that support many propagation paths or transverse modes are called multi-mode fibers, while those that support a single mode are called single-mode fibers (SMF). Multi-mode fibers generally have a wider core diameter and are used for short-distance communication links and for applications where high power must be transmitted. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft).
Being able to join optical fibers with low loss is important in fiber optic communication. This is more complex than joining electrical wire or cable and involves careful cleaving of the fibers, precise alignment of the fiber cores, and the coupling of these aligned cores. For applications that demand a permanent connection a fusion splice is common. In this technique, an electric arc is used to melt the ends of the fibers together. Another common technique is a mechanical splice, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors.
The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. The term was coined by Indian-American physicist Narinder Singh Kapany.
