Fiber Optic Specialist
Commonwealth Fusion Systems
Company Overview
Commonwealth Fusion Systems (CFS)
Cambridge, MA, United States
2018
Approximately 430 employees (source: zoominfo.com). Revenue figures vary, with reports indicating $211.3 million or $31.7 million, though as a pre-revenue fusion developer focused on R&D, these may reflect funding or operations rather than sales.
What They Do
Commonwealth Fusion Systems (CFS) is a pioneering private fusion energy company that specializes in tokamak-based magnetic confinement fusion. Founded as a spinout from MIT's Plasma Science and Fusion Center, CFS focuses on utilizing high-temperature superconducting magnets to achieve commercial net energy production (source: cfs.energy). The company has made significant strides in its technology, particularly with the development of compact fusion machines that leverage decades of tokamak science. Their flagship projects, SPARC and ARC, aim to demonstrate net energy gain and commercial viability in the coming years (source: cfs.energy).
Projects & Track Record
CFS is currently engaged in several groundbreaking projects, most notably the construction of SPARC, which is set to be the world's first net-energy fusion machine. Located at their Fusion Energy Campus in Devens, Massachusetts, SPARC aims to demonstrate net energy gain by the late 2020s (source: cfs.energy). Additionally, CFS is planning the ARC project, a 400 MW-class grid-scale tokamak power plant designed for commercial deployment in the early 2030s. These projects are underpinned by significant technological advancements, including the successful testing of the central solenoid magnet module (CSMC) in November 2024, which confirmed the manufacturability of critical components for SPARC (source: zoominfo.com).
Recent Developments
In the past two years, CFS has made remarkable progress, including the opening of its Devens Fusion Energy Campus on February 10, 2023, which was attended by notable figures such as U.S. Secretary of Energy Jennifer Granholm (source: cfs.energy). The company has also secured substantial funding, raising $863 million in August 2024, building on a previous $1.8 billion round in May 2023, bringing total funding to over $2 billion (source: wbjournal.com). Furthermore, CFS announced its first commercial power plant site in Chesterfield County, Virginia, which will be independently financed and operated, with plans for grid connection in the early 2030s (source: zoominfo.com).
Working There
CFS offers a range of roles across various disciplines, including fusion science, engineering, manufacturing, and materials science. The majority of their workforce is based at the Devens campus, which has grown to over 430 employees (source: cfs.energy). The company culture emphasizes rapid execution and transparency, attracting top talent from the fusion and manufacturing sectors. Key executives include Co-Founder and CEO Bob Mumgaard, along with other leaders in operations and science, indicating a strong demand for expertise in tough tech and physics (source: nasdaqprivatemarket.com). While specific benefits are not detailed, the scale-up and investor backing suggest competitive packages for high-caliber roles in a mission-driven environment (source: cfs.energy). Job seekers are encouraged to monitor their careers page for openings related to SPARC and ARC advancements.
Last updated on Feb 23, 2026 | Report an issue
Job Description
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 - 6:00 am to 3:00 pm.
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
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7+ years experience in fiber optics field applications
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Experience in utilizing distributed sensing arrays
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Experience with polyimide and a variety of coated fibers
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At least 1 year experience in teaching and/or training fiber splicing techniques and cable assemblies
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Experienced with designing, building, and testing fiber cable assemblies, particularly in cryogen and vacuum conditions
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Experience performing fiber optic work in environments with limited space or requiring odd positions.
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Skills:
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Fiber coating removal
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Fiber re-coating
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Specialty fiber splicing
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Fiber proof-testing
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Measurement and analysis techniques with optical tools and equipment such as interrogators, optical multiplexers, optical switches, fault locators, OTDR, etc.
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Knowledgeable about various optics sensing techniques and optical attenuation/insertion loss mechanisms
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Basic Materials Science knowledge
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Good communication skills
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Good attention to detail
Must-have Requirements
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Ability to occasionally lift up to 50 lbs
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Perform activities:
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Stooping, typing, standing, or sitting for extended periods of time
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May need to operate in small confined places in odd locations
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Work locations could include being on platforms around 25 feet high
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Dedication to safety to mitigate industrial hazards that may include heat, cold, noise, fumes, strong magnets, lead (Pb), high voltage, and cryogenics
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Willingness to travel or work required nights/weekends/on-call occasionally
$30 - $48 an hour
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
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.
Apply now
Job expired?Please let Commonwealth Fusion Systems know you found this job on Rejobs. This will help us grow and get more people to work on renewable energy!
Apply now
Job expired?Please let Commonwealth Fusion Systems know you found this job on Rejobs. This will help us grow and get more people to work on renewable energy!
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About the role
June 4, 2026
Full time
Company
- Somerville, Massachusetts, United States
4+ years in fiber optics field applications
UTC-05:00