In fiber-optic and free-space communication, beam spreading determines the maximum link distance before the signal becomes unreadable. Beam spreading is the gradual widening of an energy beam (light, sound, or radio waves) as it travels away from its source. INTRINSIC FIBER OPTIC SENSORS: In such type of sensors, sensing takes place within the fiber itself. These type of sensors have their dependency on the optical fiber properties itself to convert an environmental action into a modulation of the light beam passing. However, sensors based on fiber-optics have been developed rapidly because of their excellent sensing performances and capability to function in remote and harsh environments. Think of it like a photoresistor, which changes its resistance based.
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