The Study Of The Fabrication And The Propagation Property Of Subwavelength Diameter Optical Fiber

Subwavelength diameter fiber (SWDF) is a kind of optical fiber that its diameter is smaller than the wavelength propagated by it. Because the diameter of SWDF is much smaller than that of ordinary optical fiber, it is possible for SWDF to apply to the miniature photoelectric equipment. Meanwhile, because the propagation property of SWDF is extraordinary, this makes it become possible to make the optical fiber sensor higher in sensitivity. It can be predicted that the miniaturization of the optical fiber is an irreversible trend; the SWDF will play an important role in field of photo-communication, optical fiber sensor and integrate optics.Chemical etching method was proposed to fabricate SWDF for the first time and the propagation property of SWDF was studied in this paper.Firstly, we designed three experimental methods: coating-divested etching method, open-end etching method and close-end etching method. We studied the pluses and minuses of these three methods through experiments. Experimental result showed open-end etching method made the smoothest fiber surface but its craft was discommodious, however, coating-divested etching method was convenient in craft and the fiber surface made by it was good too. We chose coating-divested etching method to fabricate SWDF finally. The SWDF was fabricated by constantly experiments, with good diameter homogeneity and surface smoothness.Furthermore, based on electromagnetic theory and Maxwell's equation group, we studied the properties of SWDF. The result indicated that the SWDF had stronger evanescent wave characteristic than that of ordinary optical fiber. So SWDF had enormous potentiality at making high-sensitivity optical fiber sensor.Finally, we operated the SWDF under an optics microscope. Experimental results demonstrated that the SWDF had characteristics such as ultrasmall size, great flexibility and strong evanescent wave field etc. We also imagined applications of SWDF in the field of optical fiber sensor and near-field microscopy, according to the extraordinary characteristics of SWDE...