fiberopticlessonoutline

Outline for introduction to fiber optics lesson:

I. What is light?
Light is a type of energy called electromagnetic radiation. Light is produced by "excited" atoms. Electrons in an energy level have a specific amount of energy. If an electron absorbs more energy, it is bumbped to a higher energy level, producing an unstable or "excited" atom. Atoms do not like to be excited, so the electron will lose the extra energy by giving off a photon, allowing it to fall back to its original level. This produces light.

II. What are the properties of light?
     A. Light behaves like a particle and like a wave.
     B. Light travels in straight lines in the form of waves at a speed of about 300,000
          km (about 186,000 miles) per second in a vacuum such as space.
     C. When light strikes matter, four things can happen:
           1. Light can be transmitted (it passes through the substance)
           2. Light can be absorbed (it passes into the substance and is held there)
           3. Light can be reflected (it strikes the substance and bounces back)
           4. Light can be refracted (the bending of light as it passes through materials of
                different densities)

III. Fiber Optics
     A. Optical fibers work by totally reflecting the light inside so that none of it leaks
           out. (Use Fiber Optics Demonstrator to illustrate this - available in the Sargent-
            Welch catalog)
     B. Most common application is telecommunication.
     C. Benefits of fiber optics:
          1. One pair of copper wires can carry about 30 telephone calls, while an optical
               fiber can carry up to 1,900 telephone calls at one time.
          2. Fiber optic cables cannot be tapped, making them extremely useful to the
              military.
          3. Fiber optics can move massive amounts of information at low cost in just a
              few seconds. A fiber optic system can transmit the equivalent of a 24
              volume encyclopedia set (about 40 million words) in a single second.
     D. Laser light is used because it is both coherent (it has only one wavelength) and
          it is monochromatic (one color), while white light is a mixture of colors and
          wavelengths. ( Use a prism here to illustrate that white light from a flashlight
          can be separated into the different colors, while laser light is not)
     E. Fiber optic cables are strands of optically pure glass as thin as human hair, that
          carry digital information.
     F. A fiber optic relay system consists of the following:
          1. transmitter - produces and encodes the light signals
          2. optical fiber - conducts the light signals
          3. optical receiver - receives and decodes the light signals.

IV. Oscilloscope - Used to measure amplitude and voltage.
      Demonstrate how the oscilloscope works using the voice links.