Since the nature of this project will be using the fiber optic cable to transmit audio signal, it is essential to understand how fiber optic transmission works and also the construction of the fiber cable, how light propagate in an optical fiber, dispersion characteristics, various connector types, bandwidth, operation of light emitting diodes etc. in order to understand all these topics I'm totally aware of that an intensive research needed to be done. Optical fiber uses light pulse to transmit information from one point to another. So light will act as a carrier and carry modulated signal using light pulse through optical cable and at the receiver end the photodiode will detect the signal and convert it back to electrical signal. So the fiber is a waveguide and basically guide the light to the end to the receiver. The most important of light propagate within the fiber is Snell's Law, which is from basic physics. So the Snell's law is all about refraction and the bending of light as it goes from one medium to another. There are different types of optical fiber cable such as single mode, multimode and plastic optical fiber. It is necessary to decide which type of cable to use for this project and chosen cable is a plastic optical cable because of the price. And also it can be bended up to 20mm with no change in transmission. But the downside of the plastic fiber is that the transmission reduces as the distance increase. Single mode fiber cable is much narrow, which confine the optical signal to a straighter path with less reflections and therefore reduces light dispersion and result cleaner signal. Multimode optical fiber is mostly used to transmit over short distance because it can propagate many mode and also available in graded index. The graded index is the fiber core that has a reflective index, which reduces the intermodal dispersion.
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