An optical modem is a device that converts a computer's electronic signals into optical signals for transmission over optical fiber and also converts optical signals from an optical fiber cable back into electronic signals for use by a computer.
A modem is generally defined as an electronic device that encodes digital data on to an analog carrier signal (a process referred to as modulation), and also decodes modulated signals (demodulation). This enables computers' digital data to be carried over analog networks, such as cable television lines and the conventional telephone network (sometimes referred to as the public switched telephone network or PSTN).
Optical modems employ a very different type of technology than modems used with copper wire media (i.e., dial-up, DSL and cable modems), and thus the use of the word modem in their name might not be the most appropriate terminology. Consequently, the terms optical transceiver and optical media adapter are also sometimes used.
Optical modems provide much higher data transmission rates than are possible with other types of modems because of the extremely high capacity of the optical fiber cable through which the data is transmitted. They are not commonly used by ordinary consumers because of the generally sufficient speeds that are now attainable over copper wire cable TV and telephone lines at a relatively low cost.
Created December 3, 2005.