Photonic switching devices

Light signals travel in optical fibers over hundreds of kilometers and are still detected. This extraordinary transmission phenomena turned optical communications into a successful technology in a very short time. Why is light so good for transmission? The fundamental reason has to do with the fact that light is not perturbed easily: a photon is a very inert particle. It is not easy to deflect a photon from its course. Unlike electrons it will not be affected by charges or by the presence of other photons. Only the interaction of light with matter can affect its propagation. By a proper choice and careful preparation, very transparent materials can be made. Moreover, photons are relatively easy to generate and detect using absorbing transitions. (Neutrinos could propagate with even less loss, but alas, they are very difficult to create and detect!)

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