The advent of the multimode photonics era requires new devices for on-chip modal control. One of the most important applications is the simultaneous and uniform excitation of pairs of distinct modes. This represents a fundamental key-step for nonlinear multimode operations, where couple of different spatial modes should be excited in-phase and should preserve the temporal synchronisation. In this work we design, fabricate and test integrated silicon nitride asymmetric tapers, whose central longitudinal axis is shifted with respect to the axis of the corresponding waveguide. By controlling the centre-to-centre shift S between taper and waveguide, we achieve simultaneous and in-phase excitation of both the TE00 (TM00) and the TE01 (TM01) mode, with a power ratio that depends on S.
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