Optical Fiber Technology
- Overview
Optical fibers are flexible, transparent fibers made by drawing glass (silicon dioxide) or plastic to a diameter slightly thicker than a human hair.
Optical fibers are most commonly used as a means of transmitting light between the ends of a fiber and are widely used in fiber optic communications, which allow transmission at higher bandwidths (data transfer rates) and over longer distances than electrical cables. There are many types of fiber optic cables, often that end up in fiber optic cable assemblies to execute their function.
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.
- What Is Fiber Optics Used For?
Fiber optics are used instead of metal wires because there is less loss of signal as it travels along them; also, fibers are immune to electromagnetic interference, which is a problem with metal wires. Fiber optics are also used for illumination and imaging, and are often wound into bundles so they can be used to bring light into or bring images out of a confined space, as in the case of fiberscopes. Specially designed fibers are also used in a variety of other applications, some of which are fiber optic sensors and fiber lasers.
- How Does a Fiber Optic Cable Work?
Optical fibers generally include a core surrounded by a transparent cladding material having a lower refractive index. Light is retained in the core by the phenomenon of total internal reflection, allowing the fiber to act as a waveguide. A fiber that supports multiple propagation paths or transverse modes is called a multimode fiber, while a fiber that supports a single mode is called a single-mode fiber (SMF). Multimode fiber typically has a wider core diameter and is used for short-distance communication links and applications where high power must be transmitted. Single-mode fiber is used for most communication links longer than 1,050 meters (3,440 feet).
Being able to connect optical fibers with low loss is very important for optical fiber communication. This is more complex than connecting wires or cables, and involves carefully cleaving the fiber, aligning the cores precisely, and coupling those aligned cores. For applications requiring a permanent connection, fusion splices are common. In this technique, an electric arc is used to fuse the ends of the fibers together. Another common technique is mechanical splices, where the ends of the fibers are held in contact by mechanical force. Temporary or semi-permanent connections are made through specialized fiber optic connectors.
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