  By a hybrid integration of plasmonic and dielectric waveguide concepts, it is
shown that coherent perfect absorption can be achieved in a co-propagant
coupler geometry. The device holds promises for classical and quantum signal
processing. First, the operating principle of the proposed device is detailed
in the context of a more general 2x2 lossy coupler formalism. Then, it is shown
how to tune the device in a wide region of possible working points, its
broadband operation, and the tolerance to fabrication uncertainties. Finally, a
complete picture of the electromagnetic modes inside the hybrid structure is
analyzed, shining light onto the potentials which the proposed device holds in
view of other applications like nonlinear optics, polarization control, and
sensing.
