Unconventional Photon Blockade in a Symmetrically Driven Nonlinear Dimer

We demonstrate unconventional photon blockade in a symmetric Kerr dimer driven with equal-amplitude fields at a $90^\circ$ phase difference. The minimum inter-cavity coupling is $J_{\min} = \gamma/4$ at a Kerr nonlinearity $U \ll \gamma$ achievable in standard photonic molecules. The quadrature-driven site emits strongly antibunched light with a smooth, oscillation-free second-order correlator directly resolvable with standard detectors. The scheme operates under continuous-wave and pulsed excitation, and fabrication disorder can be fully compensated by re-tuning the drive phase, removing the need for post-fabrication cavity trimming.