Heterogeneous III-V/Si micro-ring laser array with multi-state non-volatile memory for ternary content-addressable memories.

In this work, we introduce programmable memory elements embedded within III-V/Si light sources which facilitate non-volatile wavelength tuning. These non-volatile III-V/Si micro-ring lasers (MRLs) exhibit non-volatile wavelength shifts of  ~80 pm with  ~40 dB signal extinction ratio while consuming 0 electrical static tuning power. An array of 5 cascaded MRLs is demonstrated with each laser capable of 4 programmable non-volatile states, thus yielding 1024 unique states altogether. Write/erase operations were performed up to 100 cycles with non-volatile time duration lasting up to 24 h. These non-volatile lasers are used to demonstrate optical ternary content-addressable memories (O-TCAM) which can find utility in fast memory search and in-memory computing functions necessary for various machine learning algorithms. The end-to-end energy consumption of the non-volatile MRL O-TCAM with 5 ternary symbols is 1156 fJ/sym. This work provides an opportunity for realizing photonic memory applications in next generation non-volatile photonic systems.