Summary:Optical fibers take advantage of the total reflection of light. Its core wire is a very transparent glass filament, and it is covered with a skin cladding with a much smaller refractive index than it. In this way, the light entering the core wire can......
Optical fibers take advantage of the total reflection of light. Its core wire is a very transparent glass filament, and it is covered with a skin cladding with a much smaller refractive index than it. In this way, the light entering the core wire can only travel along the fiber through total reflection at the interface between the core wire and the outer skin cladding, and will not pass through the interface, as if it is tightly enclosed in the core wire by the outer skin cladding. Light travels in any medium and will be lost due to absorption and scattering, but some measures can be taken to reduce the loss of light when traveling over long distances.
This includes: using ultra-pure quartz glass to reduce impurities in the optical fiber; improving the structural uniformity inside the glass as much as possible; using long-wavelength laser light for conduction to improve the transmission effect of the optical fiber.
Since the light is irradiated into the non-uniform semiconductor, the light energy is absorbed by the electrons in the P region and the N region, getting rid of the bondage of the covalent bond, and generating electron-hole pairs. The more the number of electron-hole pairs, the more electrons, so that the current flowing through the semiconductor under a certain voltage condition is larger, and the effect of smaller resistance is called the photoconductive effect.