Cambridge Heavy Industries is a Cambridge, Massachusetts company developing a modular, benchtop-scale compact inertial confinement fusion system designed to produce tritium, a rare hydrogen isotope used as fuel by most fusion reactors. The company was founded in 2025 and spun out of the Nelson Lab at MIT, where researchers had spent more than twenty years studying materials under extreme conditions using laser-driven pressure waves. Its technology combines multi-ring laser excitation with focusing shock methods and fast ignition, using two main lasers to drive ignition on a flat, round fuel target.

The company states that tritium supply is limited, with an estimated 25-30 kilograms available globally, and that its compact machines can be assembled in a cleanroom using off-the-shelf equipment and enable weekly testing and upgrades. Its prototype reached pressures of 350 GPa using tens of millijoules of laser energy, and the company reports a 400x higher compression efficiency than past laser-based fusion efforts. The system is intended to run many experiments per day, with results feeding AI-driven simulations to optimize the design.

Cambridge Heavy Industries emerged from stealth in October 2026 with a $6.2 million seed round led by Azolla Ventures, with participation from Overlay, the Mass Clean Energy Center, Neta Foundation, the Rothrock family and P3A. The funds are earmarked for building its first compact fusion reactor at its Massachusetts facility, including an ultrafast laser, optical components and neutron diagnostics, and for hiring R&D and business development staff. The company plans to develop a power plant from the design in about a decade.