  Phase-locking an array of quantum cascade lasers is an effective way to
achieve higher output power and beam shaping. In this article, based on Talbot
effect, we show a new-type phase-locked array of mid-infrared quantum cascade
lasers with an integrated spatial- filtering Talbot cavity. All the arrays show
stable in-phase operation from the threshold current to full power current. The
beam divergence of the array device is smaller than that of a single-ridge
laser. We use the multi-slit Fraunhofer diffraction mode to interpret the
far-field radiation profile and give a solution to get better beam quality. The
maximum power is just about 5 times that of a single-ridge laser for
eleven-laser array device and 3 times for seven-laser array device. Considering
the great modal selection ability, simple fabricating process and the potential
for achieving better beam quality and smaller cavity loss, this new-type
phase-locked array may be a hopeful and elegant solution to get high power or
beam shaping.
