在這篇論文中，我們將會利用含有共振腔結構的非線性晶體以及其自發性參量降頻轉換(Spontaneous parametric down-conversion, SPDC)過程產生出能量-時間糾纏的窄頻雙光子，並且利用後選擇的方法以及Hong-Ou-Mandel干涉對頻率簡併的優化，我們能製備出偏振形式上的糾纏光子，即為偏振糾纏光子，接著我們會利用CHSH不等式、量子態斷層掃描、併發度(concurrence)的計算與測量來證實我們實驗上所製造的雙光子確實為偏振糾纏光子，最後我們還提供了一個純化糾纏光子的技術，我們利用了調製波包的方法，使頻率不為簡併態的糾纏光子提升了其糾纏上的性質，並且一樣利用CHSH不等式以及併發度的計算來驗證其純化效果。

In this thesis, we generate energy-time entangled narrow-band photon pairs by using nonlinear crystal with monolithic cavity and spontaneous parametric down-conversion processes. We generate the polarization entangled photons with post selection and optimize the polarization entanglement with Hong-Ou-Mandel Interferometer.
Finally, we confirm the polarization entanglement with the CHSH inequality, quantum state tomography and concurrence. We also develop a technique for purifying the entangled photons by modulating the photons.

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