Distributed and quasi-distributed fiber optic sensors are systems that connect opto-electronic interrogators to an optical fiber (or cable), converting the fiber to an array of distributed sensors. Radiation absorption excites an orbital electron to a higher energy level. These fibers are most commonly made of glass and are very thin, typically less than a tenth of the width of a human hair. Fiber optic cable. This Applications Engineering Note (AEN 135) explains and recommends standard measurement methods for characterizing optical fiber system performance. This note also provides background information on system link configurations, test equipment and system component considerations that influence. Optical transmitter coverts electrical input signal into corresponding optical signal. Popularly used optical transmitters are Light Emitting Diode (LED) and semiconductor Laser. A fiber-optic sensor is a sensor that uses optical fiber either as the sensing element ("intrinsic sensors"), or as a means of relaying signals from a remote sensor to the electronics that process the signals ("extrinsic sensors").
