  The frequency correlation (or decorrelation) of photon pairs is of great
importance in long-range quantum communications and photonic quantum computing.
We experimentally characterize a spontaneous parametric down conversion (SPDC)
source, based on a Beta-Barium Borate (BBO) crystal cut for type-II phase
matching at 1550 nm which emits photons with the positive or no spectral
correlations. Our system employs a carefully designed detection method
exploiting two InGaAs detectors.
