Theoretical And Experimental Study On Micro-Scale Liquid Core Optical Fiber

As the development of device design theory and fabrication techniques, the more requirements for performance of device and energy consumption,decreasing the size of the device, enhancing the degree of integration and integrating the photonic device, micro-electronics and photo conducting device in the nano-scale is becoming the inexorable trend. Until the end of the last century, as the development of the fiber tapering technology, the new type fiber with sub-micro and nano-scale diameter attracts people's attention once more because of its good nonlinear and dispersion characteristics. Meanwhile the liquid core optical fiber is a fiber with new type of structure. It has the big inner diameter, the big numerical aperture, the high transmission efficiency and the long useful life. Especially for the research of nonlinear optics, the research of spectrum and the detection of the fluorescence. In this thesis, we combine the liquid core optical fiber with the fiber tapering technology and present the sub-micro-diameter-scale liquid core optical fiber in a creative way. Then we complete the theoretical and practical research.Based the numerical simulations of a 3-layer-structured cylindrical waveguide, Maxwell equation and boundary conditions, we study the propagation properties of the fundamental guided-mode of the double clad sub-micro-diameter-scale liquid core optical fibers. Then we compare the results with it of the traditional sub-micro silica fiber. Taking the carbon disulfide as the fiber core for example, we finish the simulation work. They mainly contain the propagation constant, single-mode condition, mode field distribution, transmission efficiency, nonlinear parameter, group vel℃ity and total dispersion and so on. The results of simulation show that: compared with traditional sub-micro scale silica fiber, the micro-scale liquid core optical fiber posses stronger confine ability; because of the large the third nonlinear coefficient and small effective area, the sub-micro diameter liquid core optical fiber has much lager nonlinear parameter; during the scale of wavelength we are researching on, the total dispersion of the sub-micro-diameter-scale liquid core optical fiber is always negative without a zero dispersion point. For sub-micro-diameter-scale liquid core optical fiber we research on, when its inner diameter decrease to 1 or less than 1 micrometer, the outer diameter of the fiber still remain several or tens of micrometers. So it is easier for fabrication and robuster for applications compared with silica wires.For sub-micro-diameter-scale liquid core optical fiber, through filling different high refractive index liquids, we can obtain the fibers with different propagation characteristic to meet the needs of different scientific research. In the following chapters, we obtain the propagation parameters of the fibers with carbon disulfide, toluene, nitrobenzene and benzene separately. At last we simulate the process of supercontinuum generation in micro–diameter-scale liquid core optical fiber filled with carbon disulfide by solving the Nonlinear Schr?dinger equation. The results show that by adjusting the material of liquids or the inner diameter, the tunable nonlinear parameter and total dispersion can be obtained. The simulation results of supercontinuum spectral with 1000nm span is obtained using the sub-micro-diameter-scale liquid core optical fiber filled with carbon disulfide with 1cm length and 0.5μm inner diameter. The length of fiber is much shorter than the traditional one.Considering the characteristic that the index of liquids is sensitive to the temperature, we fill the mixture between toluene and chloroform into the hollow fiber to form a new kind of intensity-modulated temperature sensor. For this sensor, by simply adjusting the proportion of the mixture, the high sensitivity and the broad measuring range. The experiments realize the measurement in 20-60℃. The sensitivity of sensor is from 4 dB/K to 5 dB/K. Another advantage of the sensor is easy to fabricate and cheap. .