optical fiber preform manufacturing technologies patents

In the 1930s, Heinrich Lamm showed that one could transmit images through a bundle of unclad optical fibers and used it for internal medical examinations, but his work was largely forgotten. Image transmission through tubes was demonstrated independently by the radio experimenter Clarence Hansell and the television pioneer John Logie Baird in the 1920s. Practical applications such as close internal illumination during dentistry followed, early in the twentieth century. In the late 19th century, a team of Viennese doctors guided light through bent glass rods to illuminate body cavities. For water this angle is 48☂7′, for flint glass it is 38☄1′, while for a diamond it is 23☄2′.

The angle which marks the limit where total reflection begins is called the limiting angle of the medium. If the angle which the ray in water encloses with the perpendicular to the surface be greater than 48 degrees, the ray will not quit the water at all: it will be totally reflected at the surface. When the ray passes from water to air it is bent from the perpendicular. When the light passes from air into water, the refracted ray is bent towards the perpendicular. Tyndall also wrote about the property of total internal reflection in an introductory book about the nature of light in 1870: John Tyndall included a demonstration of it in his public lectures in London, 12 years later.

ĭaniel Colladon and Jacques Babinet first demonstrated the guiding of light by refraction, the principle that makes fiber optics possible, in Paris in the early 1840s. The term was coined by Indian-American physicist Narinder Singh Kapany. The field of applied science and engineering concerned with the design and application of optical fibers is known as fiber optics. Temporary or semi-permanent connections are made by means of specialized optical fiber connectors. Another common technique is a mechanical splice, where the ends of the fibers are held in contact by mechanical force. In this technique, an electric arc is used to melt the ends of the fibers together. For applications that demand a permanent connection a fusion splice is common. 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. īeing able to join optical fibers with low loss is important in fiber optic communication. Single-mode fibers are used for most communication links longer than 1,050 meters (3,440 ft). 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. 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). Light is kept in the core by the phenomenon of total internal reflection which causes the fiber to act as a waveguide. Optical fibers typically include a core surrounded by a transparent cladding material with a lower index of refraction. Specially designed fibers are also used for a variety of other applications, some of them being fiber optic sensors and fiber lasers. 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. Fibers are used instead of metal wires because signals travel along them with less loss in addition, fibers are immune to electromagnetic interference, a problem from which metal wires suffer. Optical fibers are used most often as a means to transmit light between the two ends of the fiber and find wide usage in fiber-optic communications, where they permit transmission over longer distances and at higher bandwidths (data transfer rates) than electrical cables. A TOSLINK fiber optic audio cable with red light shone in one endĪn optical fiber, or optical fibre in Commonwealth English, is a flexible, transparent fiber made by drawing glass ( silica) or plastic to a diameter slightly thicker than that of a human hair.

Optical fiber preform manufacturing technologies patents