  Photonic signal processing is essential in the optical communication and
optical computing. Numerous photonic signal processors have been proposed, but
most of them exhibit limited reconfigurability and automaticity. A feature of
fully automatic implementation and intelligent response is highly desirable for
the multipurpose photonic signal processors. Here, we report and experimentally
demonstrate a fully self-learning and reconfigurable photonic signal processor
based on an optical neural network chip. The proposed photonic signal processor
is capable of performing various functions including multichannel optical
switching, optical multiple-input-multiple-output descrambler and tunable
optical filter. All the functions are achieved by complete self-learning. Our
demonstration suggests great potential for chip-scale fully programmable
optical signal processing with artificial intelligence.
