  We present the experimental implementation of double Bragg diffraction of
Bose-Einstein condensates (BECs) as proposed in [E. Giese, A. Roura, G.
Tackmann, E. M. Rasel, and W. P. Schleich, Phys. Rev. A \textbf{88}, 053608
(2013)]. We excite Rabi oscillations between the three coupled momentum states
$\left| 0 \hbar k \right\rangle$ and $\left| \pm 2 \hbar k \right\rangle$. By
selecting appropriate interaction times we generate highly efficient
beamsplitters and mirrors for Bose-Einstein condensates. In addition, we
demonstrate higher-order double Bragg diffraction and display beamsplitters
with up to $ \pm 6 \hbar k$ momentum transfer. We compare double Bragg
diffraction to several other experimental realizations of beamsplitters.
Finally, we show that double Bragg diffraction is well suited for matter wave
interferometry by realizing a Ramsey-type interferometer in a quasi
one-dimensional waveguide.
