  Bloch oscillations (i.e., coherent acceleration of matter waves by an optical
lattice) and Bragg diffraction are integrated into light-pulse atom
interferometers with large momentum splitting between the interferometer arms,
and hence enhanced sensitivity. Simultaneous acceleration of both arms in the
same internal states suppresses systematic effects, and simultaneously running
a pair of interferometers suppresses the effect of vibrations. Ramsey-Bord\'e
interferometers using four such Bloch-Bragg-Bloch (BBB) beam splitters exhibit
15% contrast at 24$\hbar k$ splitting, the largest so far ($\hbar k$ is the
photon momentum); single beam splitters achieve 88$\hbar k$. The prospects for
reaching 100s of $\hbar k$ and applications like gravitational wave sensors are
discussed.
