Integrated photonic computing-in-memory with 2D-addressable VCSELs arrays for phase change materials actuation

Photonic computing-in-memory (PCIM) based on non-volatile phase change materials (PCMs) offers a promising route to bypass the von Neumann bottleneck. However, its scalability and practical deployment are constrained by the integration complexity of the external optical devices required for PCM programming. Here, we propose and experimentally demonstrate an integrated PCIM module that overcomes this limitation by integrating a 2D-addressable vertical-cavity surface-emitting laser (VCSEL) array with a PCM memory bank via flip-chip technology. This approach eliminates the need for discrete fiber-optic components for PCM control. Concurrently, the 2D row-column addressing scheme reduces the required electrical interconnects for an N × N array from O(N²) to O(N), significantly alleviating wiring congestion. As a proof-of-concept, we developed a 32 × 32 VCSEL array heterogeneously integrated with a SiN-SOI crossbar memory bank comprising GST cells. The integrated cells exhibit over 70 distinct levels (>6 bits) within an 11 dB optical dynamic range, showcasing excellent multilevel capability. Leveraging this hardware, we partitioned the memory bank to simultaneously execute discrete Fourier transform (DFT), discrete cosine transform (DCT), and convolution operations via wavelength-division multiplexing (WDM), demonstrating high-fidelity parallel signal and image processing. This work establishes a scalable and high-density integration pathway for PCIM, addressing a critical barrier and paving the way for its practical deployment in advanced optical computing.