Two Einstein-Podolsky-Rosen-type experiments demonstrated recently in
our laboratory are reviewed in this paper. One is for space-time varia
bles, and the other is for spin variables. The two-particle sources us
ed in these experiments are the light quanta pairs produced from Type
I and Type II optical spontaneous parametric down-conversion, respecti
vely. Two-photon entanglement and two-photon Einstein-Podolsky-Rosen s
tates are discussed and demonstrated.