Navruz, İsaBilsel, Mustafa2021-11-232021-11-232021http://hdl.handle.net/20.500.12575/76258Optical fibers that can carry information by light have undoubtedly made the greatest contribution to the development of modern communication technologies. Optical fibers, which offer advantages such as very high communication bandwidth, low power loss, small size and safety against signal external factors, attract much attention not only in the telecommunication sector but also in different disciplines and especially in sensor technology researches. In this thesis, a research and development study was carried out on sensors that can measure refractive index, temperature and strain by deforming a standard single-mode telecommunication fiber. The effects of different geometric deformations on sensor performance by tapering and enlarging the the fiber diameter in sensor designs have been investigated and analyzed. In the first stage of the experimental studies, the optimum geometry of the sensor head for maximum sensitivity was determined by numerical calculations and simulation method. In further stages, experimental fabrication of fiber sensors were carried out by developing a setup using thermal method to taper the fiber. Refractive index, temperature and strain sensitivity were tested separately by establishing test setups for the fabricated fiber sensors and the sensor sensitivities were analyzed and reported. Also, a fiber sensor having two resonance dip points in the wavelength spectrum has been designed by shaping the fiber with a periodic grating pattern. This sensor that can measure temperature and strain simultaneously is novel in the literature with its unique design. By fabricating the designed sensor, the sensitivity of the sensor has been tested in experimental studies and successful results when compared with the literature have been obtained. As a result, it has been shown that with the geometric deformation techniques developed in this thesis, high-sensitivity and low-cost fiber sensors that can measure the refractive index, temperature and strain discretely or simultaneously can be easily fabricated.trinceltilmiş fiberperiyodik ızgaradoctoralThesis