  We present here a simple laser system for a laser cooled atom interferometer,
where all functions (laser cooling, interferometry and detection) are realized
using only two extended cavity laser diodes, amplified by a common tapered
amplifier. One laser is locked by frequency modulation transfer spectroscopy,
the other being phase locked with an offset frequency determined by an
Field-Programmable Gate Array (FPGA) controlled Direct Digital Synthesizer
(DDS), which allows for efficient and versatile tuning of the laser frequency.
Raman lasers are obtained with a double pass acousto-optic modulator. We
demonstrate a gravimeter using this laser system, with performances close to
the state of the art.
