  We investigate the generation and the evolution of two-mode
continuous-variable (CV) entanglement from system of a microwave-driven V-type
atom in a quantum beat laser. By taking into account the effects of
spontaneously generated quantum interference between two atomic decay channels,
we show that the CV entanglement with large mean number of photons can be
generated in our scheme, and the property of the filed entanglement can be
adjusted by properly modulating the frequency detuning of the fields. More
interesting, it is found that the entanglement can be significantly enhanced by
the spontaneously generated interference.
