High-bandwidth nonvolatile optical memory based on MMI-integrated racetrack resonator with embedded ReRAM

Area of Science:

• Photonics and Optical Engineering
• Materials Science
• Nonvolatile Memory Devices

Background:

• Silicon photonic devices are crucial for high-speed communication and computing.
• Integrating memory functionality into photonic circuits requires efficient light-matter interaction and broadband operation.
• Existing solutions often face limitations in bandwidth, power consumption, or scalability.

Purpose of the Study:

• To develop a nonvolatile, multilevel silicon photonic memory device.
• To achieve broadband operation and wavelength-division multiplexing (WDM) capabilities.
• To enhance light-matter interaction and reduce power consumption for memory integration.

Main Methods:

• Integration of a multimode interference (MMI) coupler with a micro-racetrack resonator (MRR).
• Embedding a resistive random-access memory (ReRAM) layer using high-index materials (BiFeO3, Al2O3) and an elevated film stack (EFS).
• Utilizing a transparent ITO electrode for improved mode confinement and conductivity.

Main Results:

• Broadened resonance linewidth (FWHM) in the 1.8-11.7 nm range (0.22-1.47 THz) due to MMI-induced stronger cavity coupling.
• Enlarged free spectral ranges (FSRs) of 9.9-16.9 nm, enhancing memory state distinguishability and operational stability.
• Demonstrated nonvolatile, multilevel memory states with wavelength shifts of 4.72 nm and 5.49 nm under 0 V operation, confirming multistate capability.

Conclusions:

• The developed CMOS-compatible photonic memory architecture offers broadband, scalable memory functionality with THz-level static optical bandwidth.
• The MMI-MRR design enables improved memory state distinguishability, channel spacing, and operational stability.
• This technology holds significant potential for optical storage, logic circuits, neuromorphic computing, and reconfigurable photonic systems.