Light pulses representing the transmitted data as bits on the media are generated by either:

Electronic semi-conductor devices called photodiodes detect the light pulses and convert them to voltages that can then be reconstructed into data frames.

Note: The laser light transmitted over fiber-optic cabling can damage the human eye. Care must be taken to avoid looking into the end of an active optical fiber.

Fiber-optic cables can be broadly classified into two types:

Figures 1 and 2 highlight the characteristics of multimode and single-mode fiber. One of the highlighted differences between multimode and single-mode fiber is the amount of dispersion. Dispersion refers to the spreading out of a light pulse over time. The more dispersion there is, the greater the loss in signal strength.