How Are Lasers Used in Telephones?
- Fiber optics use thin glass tubes to send light across distances without it diffusing. Light emitting diodes can be used, but lasers provide a much better source of controllable light.
- Complex modulators shape laser pulses that are sent through fiber optic cables. Sound can be converted into laser pulses and back into sound for telephone communications just as electricity is used in copper phone lines.
- Fiber optic cables transferring laser light have several advantages for communications over copper wire. They are more reliable over long distances and cannot be damaged by electrical interference. Fiber optics can also transfer more information on a single cable than a single copper wire. Also, fiber optic telephone lines cannot be tapped in the way that copper lines can be.
