基于周期性极化铌酸锂(PPLN)晶体的准相位匹配线性电光效应,利用邦加球理论,晶体 在不同占空比和温度下,探索了输出激光偏振态随外加电场的演变规律。研究结果发现,激光偏振的演变对外加电场E0、 晶体占空比D和温度T0非常敏感;若T0为273 K, D为0.25、0.5和0.75, 随着E0的增加,输出偏振态成周期性演变; 当D为0.5,且T0为263 K、293 K和313 K时,输出偏振态的演变表现为无规则性。合理选择一定的外加电场、 占空比和温度,可以实现任意偏振光。这些结果有助于PPLN偏振控制器的优化设计。

Based on the linear electro-optic effect with quasi-phase matching in periodically poled LiNbO3 crystal, the evolution laws of the output laser polarization with the applied electric field were explored by means of Poincare sphere theory, under different duty ratio of the crystal and temperature. It is found that the evolution of the output laser polarization is very sensitive to the applied electric field E0, the crystal duty ratio D and the crystal temperature T0. With T0 fixed at 273 K, and D fixed at 0.25, 0.5 and 0.75, the output polarization appears periodical evolution with the increase of E0. If D is 0.5, and T0 are 263 K, 293 K and 313 K, evolution of the laser polarization show irregular. Arbitrary polarized light can be performed by reasonable selection of a certain applied electric field, duty ratio and temperature. These results are helpful in optimizing design of the polarization controller based on PPLN crystal.