Neuron Circuit Using Coupled SQUIDs Gate with Flat Output Characteristics for Superconducting Neural Network

Takeshi ONOMI  Koji NAKAJIMA  

IEICE TRANSACTIONS on Electronics   Vol.E97-C   No.3   pp.173-177
Publication Date: 2014/03/01
Online ISSN: 1745-1353
DOI: 10.1587/transele.E97.C.173
Print ISSN: 0916-8516
Type of Manuscript: Special Section PAPER (Special Section on Leading-Edge Technology of Superconductor Large-Scale Integrated Circuits)
superconducting circuit,  SQUID,  neural network,  combinatorial optimization problem,  

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We propose an improved design of a neuron circuit, using coupled SQUIDs gates, for a superconducting neural network. An activation function with step-like input vs. output characteristics is desirable for a neuron circuit to solve a combinatorial optimization problem. The proposed neuron circuit is composed of two coupled SQUIDs gates with a cascade connection, in order to obtain such characteristics. The designed neuron circuit is fabricated by a 2.5kA/cm2 Nb/AlOx/Nb process. The operation of a fabricated neuron circuit is experimentally demonstrated. Network performance of a neural network using proposed neuron circuits is also estimated by numerical dynamic simulations.