Senior Opto-mechanical Engineer
Quick Summary
About Commonwealth Fusion Systems: Commonwealth Fusion Systems is on a mission to deliver the urgent transition to fusion energy. Combining decades of research, top talent, and new technologies,
Commonwealth Fusion Systems is currently assembling the SPARC tokamak, which aims to be the first magnetic fusion device to produce more fusion power than it consumes (Q>1). Achieving this mission depends on the diagnostic systems that deliver the scientific and controls data needed for successful
operation and provide valuable learning for ARC design. The Photonics Engineering department is seeking a Senior Opto-mechanical Engineer who will be embedded with the Long Wavelength Diagnostics team, helping to deliver diagnostic capabilities such as Laser Interferometry, Thomson Scattering, UV/VIS/IR Imaging and Spectroscopy, Electron Cyclotron Emission Radiometry, and Edge Scanning Reflectometry.
As SPARC moves from design into assembly and commissioning, this engineer will work with a cross- disciplinary team of diagnosticians, scientists, engineers, CAD designers, and technicians to close out the remaining designs and bring these systems from the tokamak, through the Tokamak Hall, and into the Diagnostic Labs. They will work to package optical and waveguide assemblies and the design of active and passive alignment systems that keep long beam paths aligned through thermal cycles, machine motion, and harsh environments expected during the operation of SPARC (high magnetic fields, vacuum, and radiation). As a senior member of the team, they will lead opto-mechanical work on medium to long-term problems, mentor other engineers, and help build CFS’s core competency in opto-mechanics for future CFS project work.
Lead the opto-mechanical design and close-out of remaining SPARC long wavelength diagnostic sub- systems (Laser Interferometry, Thomson Scattering, UV/VIS/IR Imaging and Spectroscopy, ECE, and Edge Scanning Reflectometry), carrying designs through final design review, release, procurement, and build
Design mounts, enclosures, and packaging for optical and waveguide assemblies (mirrors, lenses, windows, fiber bundles, metallic and corrugated waveguide, and quasi-optical components) along beamlines from the tokamak, through the Tokamak Hall, to the Diagnostic Labs
Design and implement active and passive alignment systems (kinematic and flexure mounts, motorized stages, alignment references, and position or beam-pointing sensing) to establish and maintain alignment over long paths and through thermal and mechanical disturbances
Develop tolerance and alignment error budgets, perform or direct structural, thermal, and vibration (FEA / STOP) analyses, feeding results back into the optical and microwave designs
Work side-by-side with diagnosticians, scientists, and optical/microwave engineers to turn measurement requirements into detailed, cost-effective, manufacturable designs, and manage interfaces with the tokamak, building, and mechanical integration teams
Work with CAD designers to produce models and drawings (GD&T), prepare specifications and design review packages; work with vendors and machine shops on build, inspection, and cost/lead-time tradeoffs
Plan and provide hands-on support for assembly, installation, alignment, calibration, and commissioning in the Tokamak Hall and Diagnostic Labs; resolve technical issues found during manufacturing and installation
Provide technical leadership and mentorship; review the work of other engineers, designers, and contractors, and contribute to Photonics Engineering opto-mechanical standards, workflows, and best practices
Contribute to a strong safety culture, including laser, microwave, vacuum, and high magnetic field safety practices, while helping commission and operate SPARC diagnostics
Location & Eligibility
About this job
- Pay per year
- $134,000–$205,000 a year
- 28% above the $132,050 median for Mechanical Engineer jobs on Jobera (903 salaries).
- Who can apply
- United States
- Posted
- Today
Listing Details
- Posted
- November 12, 2026
- First seen
- November 12, 2026
- Last seen
- November 12, 2026
Posting Health
- Days active
- 0
- Repost count
- 0
- Trust Level
- 81%
- Scored at
- November 12, 2026
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