Excitatory and inhibitory optical neuron implementation using lasing wavelength switching in edge-coupled InAs/InGaAs/GaAs quantum dot lasers

We report on lasing wavelength switching effects in InAs/InGaAs/GaAs quantum dot (QD) edge-emitting lasers activated by electrical and additional optical pumping provided by another edge-coupled QD laser. The lasers under study operate either on the ground state (GS) or on the excited state (ES). Optical pumping is provided by either GS (1260 nm) or ES (1180 nm) emission. Thus, we have evaluated four combinations of lasing modes and pumping wavelengths. Pumping of QD laser operating on ES transition with light from the GS transition results in suppression of ES lasing, with only GS emission detected. In the other three cases, optical pumping does not change the lasing mode. The switching effects resemble the behavior of biological neurons and can be useful for designing neuromorphic photonic integrated circuits.