Integer quantum Hall edge channels in 2-dimensional electron gases have remarkable transport properties of chirality and quantum coherence, which are spectacularly employed in electronic interferometers. A new class of interferometers might be available if coherent states superposed between co-propagating channels could be prepared and manipulated. In this talk we analyze theoretically the mechanisms of coherent channel mixing between edge channels, namely the presence of non-adiabatic potentials and spin-dependent couplings. Then we present a general technique employing periodic spatial modulations of the Hall-bar in order to control the phase difference and charge superposition between propagating edge states. Numerical Simulations of recently performed and future experiments will be discussed.