Realizing a lithium niobate multimode interference waveguide-based optical memory with a tri-layer resistive random-access memory structure

We report a novel non-volatile optical memory by integrating a miniaturized resistive random access memory (ReRAM) onto a Ti-diffused lithium niobate (LiNbO3) multi-mode interference (MMI) coupler. The ReRAM features an Ag / Al2O3 / CsPbBr3 QDs / Al2O3 / ITO trilayer structure. The CsPbBr3 perovskite quantum dots switching layer exhibits excellent ion mobility, enabling stable, low-power resistive switching via the synergistic migration of silver ions (Ag+), bromine vacancies (VBr+), and oxygen vacancies (VO2+) to form conductive paths. Dual Al2O3 layers function as protective and ion-diffusion barriers, ensuring controllable, gradual switching. Electrically controlling the ReRAM state induces localized refractive index changes, allowing for non-volatile phase modulation of the MMI waveguide. This enables multidimensional optical readout by simultaneously controlling output power, splitting ratio, and transmission spectrum. This work not only empowers this integrated device for memory and modulation but also provides an idea for future high-performance, reconfigurable, and low-power photonic neuromorphic platforms.