  Motivated by rapidly advancing capabilities for extensive nanoscale
patterning of optical materials, I propose an approach to implementing photonic
sequential logic that exploits circuit-scale phase coherence for efficient
realizations of fundamental components such as a NAND-gate-with-fanout and a
bistable latch. Kerr-nonlinear optical resonators are utilized in combination
with interference effects to drive the binary logic. Quantum-optical
input-output models are characterized numerically using design parameters that
yield attojoule-scale energy separation between the latch states.
