Fiber-optic Communication is a method of transmitting information from one place to another by sending light through an optical fiber.An optical fiber (or fiber) is a glass or plastic fiber that carries light along its length. Light is kept in the "core" of the optical fiber by total internal reflection.The light forms an electromagnetic carrier wave that is modulated to carry information.Theprocess ofcommunicatingusing fiber-optics involves the following basic steps: Creating the optical signal using a transmitter, Relaying the signal along the fiber, ensuring that the signal does not become too distorted or weak, and receivingthe optical signal andconvertingit into an electrical signal.Pulses of electricity corresponding to the bits arrive at the input transducerA device that converts one form of energy to anotherDevices similar to light bulbs are used as optical transducers at the input of fiber-optic cables to convert electricity into lightLight emitting diodes (LED)Laser diodes (LD)Electrical signals arriving at the input of optoelectronic devices are used to modulate the light sourceThe modulated optical signal is emitted by the source and coupled into the cableOnce the light is trapped inside the cable, it travels to the other end, where it is demodulated and an output transducerPhotodiode (PD) or phototransistorAdvantages of fiber opticsMuch Higher Bandwidth (Gbps) - Thousands of channels can be multiplexed together over one strand of fiberImmunity to Noise - Immune to electromagnetic interference (EMI).Safety - Doesn't transmit electrical signals, making it safe in environments like a gas pipeline.High Security - Impossible to "tap into."Less Loss - Repeaters can be spaced 75 miles apart (fibers can be made to have only 0.2 dB/km of attenuation)Reliability - More resilient than copper in extreme environmental conditions.Size - Lighter and more compact than copper.Flexibility - Unlike impure, brittle glass, fiber is physically very flexible.Disadvantages of fiber optics: Disadvantages include the cost of interfacing equipment necessary to convert electrical signals to optical signals. (optical transmitters, receivers) Splicing fiber optic cable is also more difficult.
