| The detection of the characteristic of oil-film on water surface and thin-film thickness is a topic that has been of considerable interest for a long time. In particular, this technique has widespread application in areas as chemical analysis, oil field exploration, industrial processing control, environmental protection, etc. The necessity of versatile methods to measure the characteristic of oil-film on water surface that suffer from ambiguity problem is still unsatisfied.These years, an optical fiber sensor technique based on the white-light interferogram is presented to introduce an absolute position measurement method. The system employs a wide band source (i.e., a few tens of nanometers) with a low coherence length (i.e., a few tens of micrometers) that gains a narrow interference pattern. The technique proved to be a convenient method providing the combination of absolute position measurement with a large dynamic range and high accuracy.In this thesis, a technique of scanning white-light interferometer in Michelson configuration is employed to measure and analyze the characteristics of different types of oil-film on water surface. This technique is capable not only of probing the thickness of oil-film on water surface but also of discriminating the types of oil-film on water surface. The ambitious work of this thesis is to find the fact that the interface of oil with water is able to reflect white-light beam good enough to form an interferogram, even if it is subjected to oil-film dispersion. So both the reflections of the oil-film surface and the interface of oil-film with water are good enough to form a surface and an interface interferogram, respectively. A new criterion is derived theoretically and tested experimentally by carefully calculating the intensity ratio of the central fringes of the surface interferogram and the interface one. Experimental results show that this method is robust to the intensity fluctuation even if it is intensity-based.
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