  The collective response of a system is profoundly shaped by the interaction
dynamics between its constituent elements. In physics, tailoring these
interactions can enable the observation of unusual phenomena that are otherwise
inaccessible in standard settings, ranging from the possibility of a Kramer's
degeneracy even in the absence of spin to the breakdown of the bulkboundary
correspondence. Here, we show how such tailored asymmetric coupling terms can
be realized in photonic integrated platforms by exploiting non-Hermitian
concepts. In this regard, we introduce a generalized photonic molecule composed
of a pair of microring resonators with internal S-bends connected via two
directional couplers and a link waveguide. By judiciously designing the
parameters of this system, namely the length of the links and the power
division ratio of the directional couplers, we experimentally show the
emergence of Hermitian and non-Hermitian type exchange interactions. The
ramifications of such coupling dynamics are then studied in 1D chain and
ring-type active lattices. Our findings establish the proposed structure as a
promising building block for the realization of a variety of phenomena,
especially those associated with phase locking in laser arrays and
non-Hermitian topological lattices.
