Fiber optic sensing technology is one of the fastest growing technologies in the modern day science. Optical fiber sensors draw more and more interests of researchers and application engineers for its exclusive and very valuable characteristics. It is mainly used to sense the physical and chemical properties such as micro-bending, strains, vibrations, accelerations, linear and rotary position, temperatures, pressures, determination of pH, refractive index of liquid solution, pipeline condition monitoring etc. furthermore, fiber optic sensors have a variety of special benefits for example faster response, low-cost fabrication, very light weight, highly sensitive plus non-reactive to electromagnetic interference. Fiber optic sensors can also be classified under various types based on sensing methods and applications. These distinctive and valuable application features facilitate an extensive range of industries such as biomedical, aerospace, structural health monitoring, transportation, oil-pipe condition etc. This paper discusses about the basic working principle of fiber optic sensing technology, various types of fiber optic sensors and their applications and future scope of fiber optic sensors. This paper also discusses about PDMS materials as the coating for fiber optic sensors for improved and enhanced performance.