Engineering of fast mode conversion in multimode waveguides.

We propose fast and robust mode conversion in multimode waveguides based on Lewis-Riesenfeld invariant theory. The design of mode converters using the multimode driving for dynamical invariant is discussed. Computer-generated planar holograms are used to mimic the shaped pulses driving the states in three-level quantum systems. We show that the invariant-based inverse engineering scheme reduces mode converter length as compared to the common adiabatic scheme.