  We study theoretically and experimentally the influence of temporally shaping
the light pulses in an atom interferometer, with a focus on the phase response
of the interferometer. We show that smooth light pulse shapes allow rejecting
high frequency phase fluctuations (above the Rabi frequency) and thus relax the
requirements on the phase noise or frequency noise of the interrogation lasers
driving the interferometer. The light pulse shape is also shown to modify the
scale factor of the interferometer, which has to be taken into account in the
evaluation of its accuracy budget. We discuss the trade-offs to operate when
choosing a particular pulse shape, by taking into account phase noise
rejection, velocity selectivity, and applicability to large momentum transfer
atom interferometry.
