Application of a reconfigurable all-optical activation unit based on optical injection into a bistable Fabry-Perot laser in multilayer perceptron neural networks.

In this Letter, we theoretically investigate the application of a bistable Fabry-Perot semiconductor laser under optical injection as an all-optical activation unit for multilayer perceptron optical neural networks. The proposed device is programmed to provide reconfigurable sigmoid-like activation functions with adjustable thresholds and saturation points and benchmarked on machine learning image recognition problems. Due to the reconfigurability of the activation unit, the accuracy can be increased by up to 2% simply by adjusting the control parameter of the activation unit to suit the specific problem. For a simple two-layer perceptron neural network, we achieve inference accuracies of up to 95% and 85%, for the MNIST and Fashion-MNIST datasets, respectively.

Reconfigurable all-optical bistability/tristability in dual injection-locked Fabry-Perot laser diodes.

In this Letter, we present a detailed theoretical and experimental investigation of optical bistability and tristability in dual injection-locked Fabry-Perot laser diodes. The proposed device can be reconfigured between the bistable and tristable regimes, simply by adjusting the power level of the injected control optical signal. The tristability presented in the experiment is achieved for relatively low optical input powers between 1.03 and 1.25 mW, with the output signal ratio of up to 7 dB between stable states. Such a device is a potential candidate for designing trits, a bit analogy in ternary computational logic.

Generation of a dual optical frequency comb by large signal modulation of a semiconductor laser.

In this paper, we present and theoretically investigate a simple and power efficient scheme for dual optical frequency comb generation residing on a single directly modulated semiconductor laser driven by two superimposed current waveforms. Our detailed model estimates dual combs comprising teeth pairs within 20 dB margin spanning up to 116 GHz with power per teeth pair up to 8.8 µW. In addition, we report dual combs with 40 GHz span comprising ultraflat teeth pairs, with flatness of the order of 1 dB.

Switching time in optically bistable injection-locked semiconductor lasers.

Switching between states in a dispersive bistable injection-locked slave laser has been theoretically investigated. We show that the switching can be achieved by relatively small and short (≈10-50 ps) variation of the master laser injection power or frequency, which, besides the variation of the slave laser optical power, leads to significant variation of its photon phase (≈5π/6). By using an analytical model, we calculate the switching time dependence on the magnitude of the injection power and the frequency detuning variation.