Fiber Optic Specialist
Commonwealth Fusion Systems
Devens, MA, USA
USD 30-48 / hour + Equity
Posted on May 11, 2026
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, we’re designing and building commercially viable fusion power plants. And we're working with policymakers and suppliers to build the energy industry of the future.
We’re in the best position to make it happen. Since 2018, we’ve raised nearly $3 billion in capital, making us the largest and leading private fusion company in the world.
Now we’re looking for more thinkers, doers, builders, and makers to join us. People who’ll bring new perspectives, solve tough problems, and thrive as part of a team.
If that’s you and this role fits, we want to hear from you.
Join the power movement as a Fiber Optic Specialist
The Fiber Optic Specialist on the SPARC Assembly Team is an exciting and evolving role with a responsibility for performing all aspects of optical fiber work such as fiber handling, splicing, testing, and incorporation of fibers into complex design features in the process of assembling our fusion machine. The technician will ensure functional installation, health, and operation of the fibers, as well as look for opportunities for continuous improvement. Responsibilities include close cooperation with Operations, Engineering, Quality, and other departments to ensure goals and objectives are met. This role will lead the way to making Earth sustainable for the future to come.
This work is conducted within a multi-disciplinary team of technicians and engineers. Participation and clear, concise communication while working with the team is crucial.
This position will cover the first shift - 7:00 am to 3:00 pm, with opportunities for overtime in certain periods related to schedule needs.
What you'll do:
- Conduct the handling, routing, splicing, testing, and potential repair of 1000’s of fibers throughout the SPARC fusion machine
- Perform mechanical integration of small assemblies adjacent or in conjunction with the fiber work, such as passthrough flanges and enclosures for the fibers
- Install composite or polymer wrappings for the fibers and their enclosures
- Train other technicians as needed in the proper installation, splicing, routing, and measurement procedures
- Improve safety protocols for laser and fiber optic handling
- Fulfill manufacturing and R&D fiber needs
What we’re looking for:
- 4+ years experience in fiber optics field applications
- Experience with taking attenuation, insertion loss, and spectral analysis measurements using various measurement equipment (such as OTDR, OSA, OBR, power meter, etc.)
- Must have experience fiber handling in a lab setting with known standards
Bonus points for:
- 7+ years experience in fiber optics field applications
- Experience in utilizing distributed sensing arrays
- Experience with polyimide and a variety of coated fibers
- At least 1 year experience in teaching and/or training fiber splicing techniques and cable assemblies
- Experienced with designing, building, and testing fiber cable assemblies, particularly in cryogen and vacuum conditions
- Experience performing fiber optic work in environments with limited space or requiring odd positions.
- Skills:
- Fiber coating removal
- Fiber re-coating
- Specialty fiber splicing
- Fiber proof-testing
- Measurement and analysis techniques with optical tools and equipment such as interrogators, optical multiplexers, optical switches, fault locators, OTDR, etc.
- Knowledgeable about various optics sensing techniques and optical attenuation/insertion loss mechanisms
- Basic Materials Science knowledge
- Good communication skills
- Good attention to detail
Must-have Requirements:
- Ability to occasionally lift up to 50 lbs
- Perform activities:
- Stooping, typing, standing, or sitting for extended periods of time
- May need to operate in small confined places in odd locations
- Work locations could include being on platforms around 25 feet high
- Dedication to safety to mitigate industrial hazards that may include heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, and cryogenics
- Willingness to travel or work required nights/weekends/on-call occasionally
#LI-Onsite
At CFS, we excel in fast-paced environments, driven by our values of integrity, execution, impact, and self-critique. As we grow, we’re eager to bring on mission-driven folks who offer diverse perspectives and fresh ways to tackle challenges.
We value diversity deeply and are proud to be an equal opportunity employer by choice. We consider all qualified applicants equally, regardless of race, color, national origin, ancestry, citizenship status, protected veteran status, religion, physical or mental disability, marital status, sex, sexual orientation, gender identity or expression, age, or any other basis protected by law.
This role requires compliance with U.S. laws concerning the export of controlled or protected technologies or information (collectively, “Export Control Laws"). Any offer of employment will be contingent on the need for compliance with such Export Control Laws.
30 - 48 USD
Salary range for this full-time position + equity + benefits. The actual salary will depend on level, location, qualifications, and experience. The range displayed on each job posting reflects new hire salaries for the position across all US locations. Benefits include:
• Competitive compensation with equity
• 13 Company-wide Holidays
• Flexible vacation days
• 10 sick days
• Generous parental leave policy
• Health, dental, and vision insurance
• 401(k) with employer matching
• Professional growth opportunities
• Team-building activities