Interferometry

Engineering

Artificial intelligence

Telecommunications

Physics

Optical transfer function

Transfer function

Multiplexing

Optics

Wavelength-division multiplexing

Acoustics

Sigmoid function

Optical amplifier

Computer science

Modulation (music)

Electrical engineering

Laser

Wavelength

Artificial neural network

Optics Express

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.

An all-optical neuron with sigmoid activation function