  We propose a linear compression technique for the time interval distribution
of photon pairs. Using a partially frequency-entangled two-photon (TP) state
with appropriate mean time width, the compressed TP time interval width can be
kept in the minimum limit set by the phase modulation, and is independent of
its initial width. As a result of this effect, ultra-narrow TP time interval
distribution can be compressed with relatively slow phase modulators to
decrease the damage of the phase-instability arising from the phase modulation
process.
