  We propose a scheme to manipulate quantum correlation of output lights from
two sides of a cavity by phase control. A probe laser is set to split into two
beams in an interferometer with a relative phase in two arms which drive the
cavity mode in opposite directions along cavity axis, individually. This phase,
here named as driving-field phase, is important to build up quantum correlation
in HBT (Hanbury Brown-Twiss) setup. Three control lasers propagate vertically
to the cavity axis and drive the corresponding atomic transitions with a
closed-loop phase. This type of closed-loop phase has been utilized to realize
quantum correlation and even quantum entanglement of the atomic system in
previous work [Phys. Rev. A 81 033836 (2010)]. The scheme here is useful to
manipulate steady and maximum quantum correlation.
