  Crystalline Whispering Gallery Mode Resonators (WGMRs) have been shown to
facilitate versatile sources of quantum states that can efficiently interact
with atomic systems. These features make WGMRs an efficient platform for
quantum information processing. Here, we experimentally show that it is
possible to generate polarization entanglement from WGMRs by using an
interferometric scheme. Our scheme gives us the flexibility to control the
phase of the generated entangled state by changing the relative phase of the
interferometer. The S value of the Clauser-Horne-Shimony-Holt's inequality in
the system is $2.45 \pm 0.07$, which violates the inequality by more than 6
standard deviations.
