High Extinction Ratio Optical Switch Technology Research

With the quickly development of modem science, the matter that the high Voltage Contrast Ratio(VCR) electro-optic switch being used as a new type of electro-optic modulator in many fields has attracted more and more scientists' notice. The mainly topics of the article are to research into the characteristics of thehigh VCR electro-optic switches and design a new switch system.On the basis of the linear theory of the polarized light and the theory of the electric field, we have researched the influence of the nonuniformity of the electric field in the crystal of DKDP on the modulation of the phase, we also researched the influence of the temperature on the performance of the switch. In order to improve the uniformity of the electric field in the crystal, we have compared the uniformity under the action of the plane electrode with that under the action of the ring electrode. With the plane electrodes, the Contrast Ratio of the electro-optic switch also can be improved. Using the large-scale commercial Infinite Method software -ANSYS5.6.1, we have calculated the different distribution of the electric field in the crystal of DKDP with different shape of electrodes. At the same time, through the analysis of the characteristics when the polarized light passes through one electro-optic switch or more switches in series, we get the relation between the modulated phase of A and the intensity of the transmitted light and the influence of the direction of the polarization on the intensity of the transmitted light. If we want to improve the VCR more, another efficient method is to make two or more switches in series, this can make the VCR reach more than 1X104 .We have designed the system and have manufactured the high voltage pulse power, pockel cells and the casting of the pockel cells on the basis of the conclusion of the analysis. It is the first time that we take measure to get the value of VCR of the electro-optic switch through the experiment in China. We also measured the other parameters of the switch system. The outcome of the experiment proved that the performance of the switch system can meet the demands in some system.