Integrated quantum photonic circuit is a promising platform for the
realization of quantum information processing in the future. To achieve the
largescale quantum photonic circuits, the applied quantum logic gates should be
as small as possible for the high-density integration on chips. Here, we report
the implementation of super-compact universal quantum logic gates on silicon
chips by the method of inverse design. In particular, the fabricated
controlled-NOT gate and Hadamard gate are both nearly a vacuum wavelength,
being the smallest optical quantum gates reported up to now. We further design
the quantum circuit by cascading these fundamental gates to perform arbitrary
quantum processing, where the corresponding size is about several orders
smaller than that of previous quantum photonic circuits. Our study paves the
way for the realization of largescale quantum photonic chips with integrated
sources, and can possess important applications in the field of quantum
information processes