Optical cable 2

Sunday 2 May 2010

Laser Theodore H Maimann, physicists from Hughes Aircraft Co., succeeded in creating ruby laser first year 1960s. At that time, many people hoping use it as light source in optical fiber communications. In 1966, some Scientists at the company Corning Glass Works successfully fluorescent light of optical fiber in as far as 1.5 km . Research on the propagation light waves in optical fiber filled. Basically, fiber optic diameter of human hair (about 0.125 mm) includes two parts. First, the terrace and the outside of so-called cladding . As a result, the light launched into the fiber core optics in the local angle some will come reflected repeatedly in fiber. Event Such reflection is called in total. Most parts of the terrace made of glass, although there also made of plastic. Cladding parts can be made plastics and glass. Plastic cladding, which known as the plastic clad silica (PCS), unable delivering the best signal if a whole made of glass. There are at least two sources commonly used light scientists in optical fiber communications, namely light emiting diodes (LED) and Diode lasers - laser made of materials semiconductors, such as laser InGaAsP (Indium-gallium- Arsenic-phosphorus). LED gives light spread, consisting of random waves, unrelated to each other. Laser produce light coherent (directional) and file rays consist of waves are lined up neatly. Said coherent laser beam and the LED is not to say coherent. In addition, light produced by laser regions have values more wavelength narrow or mirni than LED. When using LEDs, incoming rays continues having various angles come. Each ray propagate independently. Light propagating in in such optical fiber multimode. When the diameter constant minimized, under the size only have a certain light one way travel, ie parallel to the optical fiber. Such propagation mode called singular. Single mode optical fiber gives attenuation light is very small. Because the terrace of single mode optical can work with a very distant repeater. However, due to fiber size very small, not easily installing a light source well. Moreover, as light source for fiber single mode optical using a laser with carrying capacity rapidly changing information. It all makes the system very single-mode optical expensive for the short term. But now the system many single-mode applied to the lower cable marine and service system for many customers. Computer data and digital communications using a signal pulse or pulses of light. According to a mathematical theorem called Fourier series, a pulse can be decomposed into number of sinusoidal waves various frequencies or wavelength known as component- Fourier components. Light disseminated by a prism into the various range color spectrum. Therefore, the refractive index of glass different for different colors or for various lengths light waves. From the conception of physics that can also occur in pulses of light while traveling down the optical fiber. Pulse thrown into the fiber optics become increasingly broad and light propagating in optical fiber further.