R&D: Electrical Programmable Multilevel Nonvolatile Photonic RAM

Light: Science & Applications has published an article written by Jiawei Meng, Yaliang Gui, Behrouz Movahhed Nouri, Xiaoxuan Ma, Department of Electrical and Computer Engineering, George Washington University, Washington DC, 20052, USA, Yifei Zhang, Department of Materials Science & Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA, Cosmin-Constantin Popescu, Department of Materials Science & Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA, Myungkoo Kang, CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, FL, 32816, USA , Mario Miscuglio, Nicola Peserico, Department of Electrical and Computer Engineering, George Washington University, Washington DC, 20052, USA, Florida Semiconductor Institute, University of Florida, Gainesville, FL, 32603, USA, and Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, 32603, USA, Kathleen Richardson, CREOL, The College of Optics & Photonics, University of Central Florida, Orlando, FL, 32816, USA , Juejun Hu, Department of Materials Science & Engineering, Massachusetts Institute of Technology, Cambridge, MA, 02139, USA , Hamed Dalir, and Volker J. Sorger, Department of Electrical and Computer Engineering, George Washington University, Washington DC, 20052, USA, Florida Semiconductor Institute, University of Florida, Gainesville, FL, 32603, USA, and Department of Electrical and Computer Engineering, University of Florida, Gainesville, FL, 32603, USA.

Abstract: “Photonic Random-Access Memories (P-RAM) are an essential component for the on-chip non-von Neumann photonic computing by eliminating optoelectronic conversion losses in data links. Emerging Phase-Change Materials (PCMs) have been showed multilevel memory capability, but demonstrations still yield relatively high optical loss and require cumbersome WRITE-ERASE approaches increasing power consumption and system package challenges. Here we demonstrate a multistate electrically programmed low-loss nonvolatile photonic memory based on a broadband transparent phase-change material (Ge2Sb2Se5, GSSe) with ultralow absorption in the amorphous state. A zero-static-power and electrically programmed multi-bit P-RAM is demonstrated on a silicon-on-insulator platform, featuring efficient amplitude modulation up to 0.2 dB/μm and an ultralow insertion loss of total 0.12 dB for a 4-bit memory showing a 100× improved signal to loss ratio compared to other phase-change-materials based photonic memories. We further optimize the positioning of dual microheaters validating performance tradeoffs. Experimentally we demonstrate a half-a-million cyclability test showcasing the robust approach of this material and device. Low-loss photonic retention-of-state adds a key feature for photonic functional and programmable circuits impacting many applications including neural networks, LiDAR, and sensors for example.“