Researchers at UC Berkeley have developed a single-chip microprocessor that communicates directly using light, marking a significant advancement in electronic-photonic systems. The microprocessor integrates over 70 million transistors and 850 photonic components, enabling logic, memory, and interconnect functions. This chip uses a zero-change approach to integrate photonics with standard microelectronics foundry processes, allowing high-performance transistors and optics to coexist on the same chip. The chip is fabricated using a commercial 45 nm complementary metal-oxide semiconductor (CMOS) silicon-on-insulator (SOI) process, with no changes to the foundry process required for photonics integration. The microprocessor features a dual-core RISC-V instruction set architecture and an independent 1 MB static random access memory (SRAM) bank. It uses on-chip electro-optic transceivers for data input/output (I/O), enabling direct communication with off-chip components using light. The chip is designed to operate at 2.5 Gb/s, providing an aggregate memory bandwidth of 5 Gb/s. The system includes a photonically-connected main memory system, allowing the microprocessor to communicate with a remote memory array located on a second identical chip. The system demonstrates the ability to run a variety of programs, including terminal-based and graphical applications, using the optical links between the microprocessor and memory. The system also includes a thermal tuning circuit to maintain the resonant device's alignment with the laser wavelength despite temperature variations. The chip's performance is evaluated through various benchmarks, including memory tests, the "Hello World!" program, and the STREAM memory benchmark. The research team acknowledges the support of various organizations, including DARPA and the National Science Foundation. The study highlights the potential of electronic-photonic systems to revolutionize computing architecture, enabling more powerful computers from network infrastructure to datacenters and supercomputers. The work represents a significant step forward in the integration of nanophotonics with advanced CMOS processes, paving the way for future advancements in very-large scale integrated circuit (VLSI) technology.Researchers at UC Berkeley have developed a single-chip microprocessor that communicates directly using light, marking a significant advancement in electronic-photonic systems. The microprocessor integrates over 70 million transistors and 850 photonic components, enabling logic, memory, and interconnect functions. This chip uses a zero-change approach to integrate photonics with standard microelectronics foundry processes, allowing high-performance transistors and optics to coexist on the same chip. The chip is fabricated using a commercial 45 nm complementary metal-oxide semiconductor (CMOS) silicon-on-insulator (SOI) process, with no changes to the foundry process required for photonics integration. The microprocessor features a dual-core RISC-V instruction set architecture and an independent 1 MB static random access memory (SRAM) bank. It uses on-chip electro-optic transceivers for data input/output (I/O), enabling direct communication with off-chip components using light. The chip is designed to operate at 2.5 Gb/s, providing an aggregate memory bandwidth of 5 Gb/s. The system includes a photonically-connected main memory system, allowing the microprocessor to communicate with a remote memory array located on a second identical chip. The system demonstrates the ability to run a variety of programs, including terminal-based and graphical applications, using the optical links between the microprocessor and memory. The system also includes a thermal tuning circuit to maintain the resonant device's alignment with the laser wavelength despite temperature variations. The chip's performance is evaluated through various benchmarks, including memory tests, the "Hello World!" program, and the STREAM memory benchmark. The research team acknowledges the support of various organizations, including DARPA and the National Science Foundation. The study highlights the potential of electronic-photonic systems to revolutionize computing architecture, enabling more powerful computers from network infrastructure to datacenters and supercomputers. The work represents a significant step forward in the integration of nanophotonics with advanced CMOS processes, paving the way for future advancements in very-large scale integrated circuit (VLSI) technology.