  Optical packet header recognition is an important signal processing task of
optical communication networks. In this work, we propose an all-optical
reservoir, consisting of integrated double-ring resonators (DRRs) as nodes, for
fast and accurate optical packet header recognition. As the delay-bandwidth
product (DBP) of the node is a key figure-of-merit in the reservoir, we adopt a
deep reinforcement learning algorithm to maximize the DBPs for various types of
DRRs, which has the advantage of full parameter space optimization and fast
convergence speed. Intriguingly, the optimized DBPs of the DRRs in cascaded,
parallel, and embedded configurations reach the same maximum value, which is
believed to be the global maximum. Finally, 3-bit and 6-bit packet header
recognition tasks are performed with the all-optical reservoir consisting of
the optimized cascaded rings, which have greatly reduced chip size and the
desired "flat-top" delay spectra. Using this optical computing scheme,
word-error rates as low as 5*10-4 and 9*10-4 are achieved for 3-bit and 6-bit
packet header recognition tasks, respectively, which are one order of magnitude
better than the previously reported values.
