Research On The Theory And Application Of Electro-optic Effect In Quasi-phase-matching Nonlinear Optics Based On Periodically Poled Lithium Niobate

This thesis focuses the research on the theory and application of the electro-optic effect in the quasi-phase-matching(QPM) nonlinear optics based on periodically poled lithium niobate(PPLN).First, the tunability of optical parametric oscillater(OPO) in PPLN was analyzed. As we know, usually the wavelength tuning of the QPM-OPO is achieved by changing the crystal temperature, but the response is not fast. In this paper we demonstrate the wavelength tuning of the QPM-OPO by the electro-optic effect for the fast wavelength tuning. We discuss the relationship of the properties of the wavelength tuning V. S. applied voltage> working temperature and duty-cycles when the voltage applies on the single domain or the dual domain . Then we get some results: the curves of wavelength tuning properties are shown as a near-linear dependence on the applied voltage, and the tuning rate is larger with the duty-cycle decreasing when the voltage applies on the dual domain; on the contrary, the-tuning rate is smaller with the duty-cycles decreasing when the voltage applies on the single domain. In the third chapter, we analyzed the second harmonic generation (SHG)in theory just like the second chapter and get different results in different conditions. From the results, the applied voltage is too large while the voltage applies on the single domain or the whole domain in SHG process, which will spoil the PPLN crystal and can not satisfy the require in experiment.In the last chapter, a novel method of optical voltage sensing based on second harmonic generation in Periodically Poled LiNb03 is proposed. The plots showing the effect of length, duty-cycle and sensor performance are given. Some useful conclusions are deduced, which give us another new practical way to fabricate working-well optical voltage sensor.