Principal Software Engineer

Focused Energy is building clean energy technology through laser-driven inertial fusion. The Principal Software Engineer will define and own the Core Software architecture for a fusion power plant, integrating controls, hardware interfaces, calibration systems, data infrastructure, and human-machine interfaces. The role will also implement critical software, establish engineering standards, lead technical decisions, and mentor engineers.

Responsibilities:

• Define and maintain the end-to-end Core Software architecture for the fusion power plant, including device interfaces, calibration, data handling, data storage, and HMI
• Design and implement critical parts of the Core Software system using languages such as C++ and Python
• Define clear interfaces between software, control hardware, diagnostics, plant equipment, data systems, and operator tools
• Design reliable automated calibration facilities and workflows that produce traceable and repeatable results
• Set practical standards for architecture, coding, testing, observability, documentation, release, reliability, security, and fault tolerance
• Lead technical decisions across teams, mentor engineers, resolve difficult trade-offs, and grow into a lead within the Software Department

Requirements:

• Extensive experience designing and implementing control software for complex physical or industrial systems
• Extensive experience with hardware and software interfaces, including device integration and system-level troubleshooting
• Experience designing and implementing automated calibration facilities or automated calibration workflows
• Strong experience with data handling, data pipelines, metadata, and reliable data storage
• Experience designing and implementing HMI for operators or technical users
• Strong software design and implementation skills in C++, Python, or similar languages
• Ability to define architecture for complex, mission-critical systems under changing requirements and strict physical constraints
• Strong communication skills — you can explain technical decisions, risks, and trade-offs to software, hardware, science, and operations stakeholders
• Strong leadership skills — you can guide decisions, mentor engineers, build alignment, and take ownership without relying on formal authority
• Experience applying thorough testing, observability, reliability, fault tolerance, security, and documentation practices
• Experience with software for plasma, nuclear power, high-energy physics, or scientific facilities
• Experience with real-time or distributed control systems and high-throughput data acquisition
• Experience defining shared frameworks, API conventions, configuration management, or communication systems for multiple teams
• Experience writing architecture decision records or technical proposals and leading architecture reviews
• Experience growing into a department-level technical lead or coaching senior engineers
• Fluency with AI-assisted software development, or strong enthusiasm for using approved AI tools responsibly to improve quality and delivery