In addition, optical fiber sensors can be used to form an Optical Fiber Sensing Network (OFSN) allowing manufacturers to create versatile monitoring solutions with several applications, e., periodic monitoring along extensive distances (kilometers), in extreme or. This article explores the different types of Fiber Optic Sensors, their working principles, and various applications. Due to its small size, low cost and ease of fabrication leading it to replace traditional sensors which were used frequently before th birth of fiber optic sensors. Further there are many points why fiber optic sensors are used in place of traditional size and. 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"). Fibers have many uses in remote sensing. With the invention of the laser in 1960's, a great interest in optical systems for data communications began. Laser systems could send a much larger amount of data than microwave, and other electrical systems. Glass fibers. Fiber optic sensors play a key role in developing the communication system to sense & measure the change within phase, data transmission rate, wavelength, intensity, noise, uneven environmental conditions, extreme heat, high vibration, etc. These sensors are available at less cost, in small size.