information transmission [@Ref1; @Ref2]. Exciton manipulation profits from strong nonlinearity in excitonic systems mediated by their electric-dipole interactions, which can be explored for the realization of all-optical control devices [@Ref3]. In addition, the interconversion between photons and excitons can be carried out coherently, i.e., by transferring the phase information between the two systems. The latter becomes especially interesting when combined with macroscopically coherent phases of either exciton polaritons [@Ref4; @Ref5] or indirect excitons (IX) [@Ref6; @Ref7; @Ref8], which provide a new platform for exciton-based information processing. Yet, the coherent manipulation of these excitonic phases as well as their integration into optoelectronic circuits remains a great challenge.

Excitons are metastable with lifetimes normally in the *ns*-range for conventional direct excitons (DXs) and in the *ps*-range for exciton polaritons. Applications require particles with long lifetimes, which can be efficiently stored, manipulated and transported between different locations. Such a requirement is met by indirect excitons (IXs) in bilayer semiconductor systems consisting of two quantum wells (QWs) separated by a thin barrier, termed a double quantum well (DQW). As illustrated in the inset of Fig. \[Fig1\](a), the application of a transverse electric field ${F_\mathrm{Z}}$ forces the oppositely charged exciton constituents (i.e., electron and hole) 