fibers. Conventional LC switches usually work by refraction, reflection and absorption of light signals. The liquid crystal cells present in the LC switches can be selectively controlled by applying a voltage, thereby changing their polarization and refraction, allowing the light beam to pass or blocking it. For polarization, polarization splitters (PBS) are connected downstream of the liquid cell. Light refraction can be accumulated by connecting several LC switches in series. So if one LC switch has a light refraction of, say, 10 degrees, then when the light
passes through two LC switches, it will be refracted by 20 degrees. This technique of switching in series allows the light path to be changed depending on the polarization. A switching engine of LC switches consists of an optical splitter with a downstream polarizer and several liquid cells that deflect the polarized light beam at several angles.