Broadband Chaos Generation and Anti-Synchronization in a Feed-Forward Optical Neural Network via Optical Injection

The operation of an optical neural network via feed-forward (FF) configuration is experimentally simulated in the laboratory. The FF setup is tested using optical injection (OI), and the behavior of follower laser diodes (FLDs) subjected to chaotic modulation is examined. The last two laser diodes (LDs) are exposed to different weights of chaotic modulated signals through optical filtration and current modulation. Observations of the emissions from these two FLDs during FF operation are verified by frequency spectra calculated from time series data. Signal broadening is assessed by measuring the full width at half maximum (FWHM), and chaotic signal spikes are analyzed by counting the number of peaks associated with signal amplitudes for the FLDs. Additionally, LD control parameters, including the bias voltage of the influencer laser diodes FLD and two additional FLDs, are examined. A maximum FWHM of 1.8 GHz for FLD is observed with a bias voltage of 3.9V (B) and a modulated signal attenuation of -12dB. To determine the synchronization state, the correlation between the ILDs and FLDs is calculated. Results indicate fluctuations between negative and positive values, with the best correlation value ILD1-FLD4 -0.8. These results confirm anti-synchronized ILD-FLDs, which represents a promising feature for potential secure communication architectures based on chaotic optical neural networks, subject to further experimental verification.