Theory And Technology Research Of White Light Interferometry For Characterization Of Polarization-maintaining Fibers

White-light (WL) temporal-domain and spectral-domain interferometry methods have been used to measure the polarization holding and dispersion parameters of polarization-maintaining fibers (PMFs) using theory analysis and instrument fabrication. Those parameters are polarization mode coupling, polarization excitation ratio, beat length and chromatic dispersion difference of the two polarization modes of the PMFs. In addition, nano-displacement and thickness of transparent material employ white-light interferometric (WLI) technique have been measured also, which enlarges the application of this instrument.This dissertation's research is based on the development of polarization mode coupling measurement instrument that fabricated by our research team. WL temporal-domain and spectral-domain intermodal interference modal have been analyzed in theory. The instrument error modal of the polarization mode coupling measurement instrument have been analyzed based on the priciple of geometrical optics. By analyzing the optimum mount angle of the optical mounted and adaptting the dispersion compensate algorithm, the instrument can test fiber with longer than 1.2km length. This instrument can provided a useful tool to measure and control the polarization problem in high sensitivity optical fiber gyro.A new polarization excitation ratio in PMFs measurement method was proposed based on the polarization mode coupling in PMFs, and the measurement sensitivity as high as -55dB. A spectral WLI technique to measure the chromatic dispersion difference of the two polarization eigenmodes in polarization-maintaining fibers (PMFs) is presented. The measurement time of the method is as fast as five seconds and the signal-to-noise ration can be achieved at least 80dB. A sepctral-domain interference beat length measurement method was also presented based on polarization mode coupling. Spectral anomalies at the spectral switch position have been analyzed by spectral-domain interference theory. Nano-displacement sensing was achieved in this instrument according to the spectral anomalies at the switch position. In all, this instrument can measure polarization mode coupling, beat length, polarization excitation ratio, intermodal chromatic dispersion difference in PMFs and nano-displacement. 1 The instrument error modal of the polarization mode coupling measurement instrument have been analyzed. The instrument can can test fiber with 1.2km long after analyzing the optimum mount angle of the optical mounted and adaptting the dispersion compensate algorithm. The measureable fiber length of this instrument is the longgest that domestic research teams can achieved. A new polarization excitation ratio in PMFs measurement method was proposed. The excitation ratio can be determined by calculate the sum of all polarization modes coupling point's intensity and the measurement sensitivity as high as -55dB.2 A numerical dispersion compensation algorithm was presented to calculate the coupling strength for this instrument. The experimental results show that the algorithm has a high accuracy, and the absolute deviation is less than 0.63dB for short fibers.3 A theory modal of PMFs intermodal spectral-domain interference have been established. The effect of light source characteristics such as central wavelength and spectral bandwidth, and the optical path difference between the two beams on the spectral interference fringe shifts at the optical phase singularity point. Based on this theory modal, a new spectral-domain intermodal chromatic dispersion difference measurement method have been proposed. The results obtained by this method can provide usefull data for numerical dispersion compensation in polarization mode coupling measurement and polarization-maintaining fibers sensors based on intermodal interference.