Study On Electro-Optic Devices Of Integrated Micro-Domain Structure Of Crystal

Periodically poled domain structure can be achieved through the ferroelectric domains engineering, in which the spontaneous polarization vectors in adjacent domains are opposite. When the electric field is applied to periodically poled domain structure, the piezoelectric coefficient and electro-optical coefficient in adjacent domains will changes its plus-minus. These properties are widely used in new electro-optic devices and all-optical wavelength conversion and other fields. In this thesis, we study the new electro-optic devices with different shapes of ferroelectric domain structures based on the electro-optic effects of ferroelectrics domains. We designed three types of electro-optical devices with micro-domain structure of prism shape, lens shape and the linear and researched their performances. The simulation and experiment results of new devices are provided.The main works are as follows:(1) The current research and development in electro-optic devices by using properties of inversion ferroelectric domains are presented.(2) For large angle of the research of high-speed electro-optic scanning, a new electro-optic scanner was designed based on the deflecting property of the beam through the parabola shaped and half-parabola shaped deflectors, the range of the deflection angle is± 30.6°. Using the software of Rsoft, the simulation results is consistent with theoretical calculation.(3) To minimize the beam diameter of micro-size laser beam, we design a demagnifier of electro-optic modulation. Firstly, we derived the expression of Gaussian beam propagating through a set of electro-optic lens of ferroelectrics inversion domains and investigated its transmission characteristics. And then we studied the effects of number of electro-optic lens and applied voltage on the equivalent focal length. Finally, we designed a demagnifier for a micro-size collimated laser beam. The diameter of a laser beam can be minimized to 0.336 times when it cascaded 18 lens and the applied voltages were 1600V and 7000V. The properties of the demagnifier of electro-optic modulation were evaluated by beam propagation method (BPM) and the simulation results shown the good agreement with theoretical values.(4) By using the electro-optical diffraction properties of a periodically poled lithium tantalate (PPLT) at the Bragg angle, we propose a 1x4 optical splitter which can change its splitting output real-time. It outputs arbitrary splitting ratio when adjusting the applied voltage. An experimental system was set up to verify its performances. The experiments achieve the splitting ratio output of 1:0:1:0,1:1:1:1,2:1:2:1,3:1:3:1.