Demand on the high-quality optical thin films has increased because of the importance in the optical sensor technologies. The thicknesses of such films are usually shorter than the wavelength of visible light. Therefore, the optical characterization of these films is not a routine procedure especially on curved surfaces such as optical fiber. Besides, the methods in the literature and commercially available systems are either expensive, destructive or non-real time. In this thesis, it is aimed to propose a simple, inexpensive and non-destructive optical characterization method of nano-scale dielectric films on curved surfaces. The methodology of that approach can be described as the near field wavefront tracing diffraction by using structured light. In this way, it has been shown that sub-wavelength film thicknesses can be estimated. The proposed diffraction method is organized in four main stages. These are the coating of optical fibers, generation of structured light, determination of wave propagation via the near field Huygens-Fresnel wave-front tracing and sensing and processing of signal from the sensor array. Layer by layer assembly technique is used in coating process to keep under control the thickness of transparent film. Selection of various source types is about to changing of point spread function of applied field and observe the effects on intensity pattern. Using near field diffraction technique, sub-wavelength thickness of thin films can be predicted by taking the higher order components of diffraction pattern by recording at very close proximity to object. In this way, determination of thickness beyond the diffraction limits can be realized. Furthermore, the resolution of sensor array in sensing part is important since pixel size of the sensor array determines your detection limits to catch all variations on diffraction pattern. The whole process has a mathematical model with numerical analysis methods. This dissertation is about the proposing a mathematical estimation model for the optical properties of nano-scale dielectric films coated on curved surfaces. The experimental results show that near field Huygens-Fresnel wave-front tracing method by using structured light is a powerful technique.