Glasses for Light Transmission Fiber Optics

Glasses for Light Transmission Fiber Optics 17.3.2.2.1. Optical Fiber Characteristics. 

In January 1992. E. Desurvire (Columbia University Center for Telecommunications Research) reported that optical fibers made from silica glass and traces of erbium can amplify light signals when they are energized by infrared radiation. Desurvire developed an efficient radiation source (referred (o as a laser diode chip) that, when integrated into a fiber optic communication system, can increase transmission capacity by a factor of 10(1. 

The light transmission technique is most frequently used for the determination of average bubble size in gas-liquid dispersion. It has the advantages of quick measurement and on-line operation. The probes are usually made of mirror-treated glass rods (Vermeulen et al., 1955), internally blackened tubes with mirrors (Calderbank, 1958), or fiber optic light guide (Hong and Lee, 1983). 

The major elements required for fiber-optics transmission include long flexible fibers made of transparent materials such as glass, plastic, or plastic-clad silica a light-transmittal source such as a laser of light-emitting diode (LED) cables or rods lined with a reflective core medium to direct light and a receiver to capture the signal. Many systems... 

Core The central region of an optical fiber consists of a sihca-glass structure in which dopants are added to achieve the desired light transmission properties for a particular type of optical fiber. The distribution of dopants alters the index of refraction of the glass, which varies based on dopant concentration. The resulting refractive core properties are referred to as the index profile. 

Light transmission in an optical fiber takes place by total internal reflection as shown in Figure 7-39. For total internal reflections to occur, it is necessary that the transmitting fiber be coated with a material that has a refractive index that is somewhat smaller than the refractive index of the fiber material. Thus, a typical glass fiber has a core with a refractive index of about 1.6 and has a glass coaling with a refractive index of approximately 1.5. Typical plastic fibers have a polymethylmethacrylate core with a refractive index of 1.5 and have a polymer coating with a refractive index of 1.4. 

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