Abstract
Recently, we have theoretically demonstrated that optically injected microdisk lasers can be tuned in a class I excitable regime, where they are sensitive to both inhibitory and excitatory external input pulses. In this paper, we propose, using simulations, a topology that allows the disks to react on excitations from other disks. Phase tuning of the intermediate connections allows to control the disk response. Additionally, we investigate the sensitivity of the disk circuit to deviations in driving current and locking signal wavelength detuning. Using state-of-the-art fabrication techniques for microdisk laser, the standard deviation of the lasing wavelength is still about one order of magnitude too large. Therefore, compensation techniques, such as wavelength tuning by heating, are necessary.
Highlights
In Spiking Neural Networks (SNNs), information is processed by excitable neurons, that communicate with each other using pulses
Given the natural appearance of excitability in many different non-linear optical components, both lasing [2, 3, 4, 5, 6, 7] and non-lasing [8, 9, 10], there is an intrinsic advantage of implementing such networks in photonic hardware as this would allow to operate at time-scales that are orders of magnitude faster than typical biological and electronic implementations [11]
Microdisk lasers are being proposed as a basic building block for an integrated photonic SNN platform
Summary
In Spiking Neural Networks (SNNs), information is processed by excitable neurons, that communicate with each other using pulses. Similar to optically injected single-mode semiconductor lasers [4, 5, 15], this gives rise, in the vicinity of a Saddle-Node on an Invariant Circle (SNIC) bifurcation, to class I excitability, which phenomenologically resembles the well-known leaky integrate-and-fire model of a spiking neuron [16]. The importance of the phase of the trigger pulse was recently demonstrated experimentally in a single-mode semiconductor laser under optical injection [15]. One clear characteristic of the microdisk excitability is that every downward pulse in the dominant mode is accompanied by an upward pulse in the suppressed mode, of approximately the same absolute strength It is the upwards pulse we will use to excite other disks. Simulations are done using Caphe, a nonlinear circuit simulator developed in our group [17]
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