  We demonstrate a polarization-entangled photon-pair source obtained via a
type-II non-collinear quasi-phase-matched spontaneous parametric
down-conversion process with a 10-mm periodically poled KTiOPO$_4$ crystal,
which is as stable and wavelength-tunable as the well-known Sagnac
configuration scheme. A brightness of 4.2 kHz/mW is detected and a concurrence
of 0.975 is estimated using quantum state tomography. Without loss of
entanglement and brightness, the photon-pair wavelengths are tunable through
control of the crystal temperature. This improvement is achieved using the
non-collinear configuration and a stable interferometric distinguishability
compensator.
