量子纠缠态生动地阐明 了量子力学的不可分离性和非局域性，具有许多潜在的应用，包括量子密钥分发、量子通信、量子计算等。迄今为止，已经多种方法获得纠缠光子对，得到高质量的纠 缠光子对对于相关的实验和量子力学方面的研究都具有重要的意义。 本文主要介绍了与量子纠缠态、非线性晶体的自发参量下转换相关的基本概念，以及一种偏振纠缠源的产生方式，实验测量了所得纠缠光子对的极化关联，给出了极化关联曲线，并对 CHSH 不等式进行了验证。

Entangled states of quantum particles highlight the nonseparability and nonlocality of quantum mechanics vividly. It has lots of potential applications, such as cryptography, quantum communication, quantum computation et al. Several methods to get entangled photon pairs have hitherto been reported, and high quality source significantly facilitate the research of quantum optical experiments. This thesis introduces some basic concept, such as entangled states, spontaneous parametric down conversion of nonlinear crystal, and a method to get polarization entangled photon pairs. The polarization entangled states has been analysis, and CHSH inequalities has been tested.