  We present our 3.5PN computation of the (2,2) mode of the gravitational wave
amplitude emitted by compact binaries, on quasi-circular orbits and in the
absence of spins. We use the multipolar post-Newtonian wave generation
formalism, extending and building on previous works which computed the 3PN
order. This calculation required the extension of the multipolar
post-Minkowskian algorithm, as well as the computation of the mass source
quadrupole at 3.5PN order. Our result will allow more accurate comparisons to
numerical relativity, and is a first step towards the computation of the full
3.5PN waveform amplitude, which would improve the estimation of the source
parameters by gravitational wave detectors.
