Measurements and modeling of a monolithically integrated self-spiking two-section laser in InP

The self-spiking behavior of an integrated saturable absorber and gain section laser fabricated in an InP technology platform is analyzed. The gain, absorber and intensity dynamics are first inspected using the normalized Yamada model. This model shows excitable behavior as well as the relative refractory period, both of which are also present in biological neurons. Measurements of a two-section laser show irregular spike generation on the millisecond timescale, with a saturable absorber voltage controlled spike density. From our simulations, and from the quasi-random character and millisecond timescale at which these pulses occur, we conclude the laser is triggered by noise, an important characteristic in the operation of biological neurons. Simulations of the laser around the excitability threshold using a newly proposed model with an optical noise term show qualitatively similar self-spiking behavior as measured.