Open AccessAn all-optical neuron with sigmoid activation function
Author(s) -
George Mourgias-Alexandris,
Apostolos Tsakyridis,
Nikolaos Passalis,
Anastasios Tefas,
K. Vyrsokinos,
Nikos Pleros
Publication year - 2019
Publication title -
optics express
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.394
H-Index - 271
ISSN - 1094-4087
DOI - 10.1364/oe.27.009620
Subject(s) - sigmoid function , optical amplifier , wavelength division multiplexing , optics , transfer function , optical transfer function , multiplexing , modulation (music) , physics , interferometry , computer science , wavelength , telecommunications , acoustics , artificial neural network , artificial intelligence , laser , electrical engineering , engineering
We present an all-optical neuron that utilizes a logistic sigmoid activation function, using a Wavelength-Division Multiplexing (WDM) input & weighting scheme. The activation function is realized by means of a deeply-saturated differentially-biased Semiconductor Optical Amplifier-Mach-Zehnder Interferometer (SOA-MZI) followed by a SOA-Cross-Gain-Modulation (XGM) gate. Its transfer function is both experimentally and theoretically analyzed, showing excellent agreement between theory and experiment and an almost perfect fitting with a logistic sigmoid function. The optical sigmoid transfer function is then exploited in the experimental demonstration of a photonic neuron, demonstrating successful thresholding over a 100psec-long pulse sequence with 4 different weighted-and-summed power levels.