Frequency Comb Photonics Engineer

ABOUT US Infleqtion is a global quantum technology company solving the world’s most challenging problems. The company harnesses quantum mechanics to build and integrate quantum computers, sensors, and networks. From fundamental physics to leading edge commercial products, Infleqtion enables “quantum everywhere” through our ecosystem of devices and platforms. Our mission is to commercialise atom-based quantum products that provide orders of magnitude improvements in performance and computing applications. LOCATION Infleqtion has offices in the USA, United Kingdom, and Australia. This is a full-time position mainly in our Kidlington, Oxford office with the occasional requirement to be in the National Quantum Computing Centre, Harwell. Work from home permitted up to 2 days per week based on business needs and manager approval. POSITION SUMMARY Infleqtion UK is seeking a Frequency Comb Photonics Engineer to support the development, characterisation, and integration of optical frequency comb technologies for quantum systems. This is a hands-on technical role focused on designing, building, testing, and optimising frequency comb systems, including micro-comb and PIC-based approaches. The successful candidate will work closely with photonics, quantum systems, electronics, and software teams to evaluate how compact frequency comb technologies can support applications such as precision timing, sensing, laser stabilisation, atom addressing, and quantum system integration. JOB RESPONSIBILITIES The duties and responsibilities outlined below include essential functions of the role. Depending on business needs, this role may perform a combination of some or all of the following duties. Duties, responsibilities, and activities may change, or new ones may be assigned. Develop, test, and characterise optical frequency comb systems for quantum technology applications. Support design and testing of photonic components relevant to comb generation, including resonators, lasers, modulators, passive devices, and integrated photonic circuits. Build and operate optical test setups for frequency comb characterisation, stabilisation, and performance validation. Perform laser characterisation, including optical spectra, frequency noise, relative intensity noise, linewidth, and stability measurements. Characterise modulated laser systems, including high-speed waveform measurements and RF/optical measurement setups. Develop automated test methods and data analysis workflows for frequency comb and photonic device characterisation. Collaborate with integrated photonics, quantum systems, electronics, and software teams to integrate frequency comb technologies into larger systems. Work with external foundries, suppliers, and packaging partners as needed to support device development and evaluation. Document experimental results, generate technical reports, and present findings to internal stakeholders. Support risk assessments, safe operating procedures, and good laboratory practice for optical and laser-based systems. PhD in Photonics, Optoelectronics, or a related discipline; candidates with equivalent hands-on experience will also be considered. Experience developing, testing, or characterising optical frequency combs, micro-combs, ultrafast lasers, nonlinear photonic systems, or related optical technologies. Strong understanding of laser physics, nonlinear optics, optical resonators, optical frequency stabilisation, and precision optical measurement techniques. Hands-on experience with optical laboratory equipment such as optical spectrum analysers, RF spectrum analysers, photodetectors, oscilloscopes, wavemeters, frequency counters, optical power meters, and fibre/free-space optics. Experience measuring laser or comb performance, including optical spectra, RF beat notes, frequency noise, relative intensity noise, linewidth, and stability. Ability to design, align, troubleshoot, and optimise complex optical and photonic test setups. Strong data analysis skills using Python, MATLAB, LabVIEW, or similar tools. Ability to work effectively in a multidisciplinary, collaborative, and matrixed technical environment. Good verbal and written communication skills, with the ability to share technical information clearly with both specialist and non-specialist audiences. Desirable Skills and Knowledge Experience with integrated photonics, silicon photonics, or PIC-based frequency comb technologies. Experience with microresonator frequency combs, Kerr combs, electro-optic combs, or mode-locked laser systems. Familiarity with photonics simulation and layout tools such as Lumerical, Synopsys, COMSOL, or similar. Experience with laser stabilisation, optical phase locking, frequency transfer, or optical clock systems. Knowledge of quantum systems, atomic physics, atom addressing, quantum sensing, or quantum networking. Experience developing automated optical test stations or hardware-control software. Familiarity with RF/microwave measurement techniques and high-speed photonic systems. Experience working with foundries, photonic packaging partners, or external device suppliers. Understanding of laser safety and HSE practices in optical laboratory environment EQUAL OPPORTUNITY Regardless of your interest in the quantum industry, you can take pride in the fact that Infleqtion is building an ecosystem of quantum technologies and commercial products, driving the industry towards the future. Studies reveal that while men apply for jobs when they meet an average of 60% of the requirements, women and other groups tend to apply only when they meet all the criteria. If you believe you have the potential but don't meet every single point in our job advertisement, please don't hesitate to contact us! We would love to chat with you and see how you could bring great value to our team. Our goal is to find exceptional individuals who can enrich our team culture, actively contribute, and have a genuine passion for their work. Here you have freedom to embrace your whole self: who you love, your gender identity and expression, skin colour, age, appearance, disability, neurodiversity, DNA, military/veteran status, citizenship, and other factors that make up who you are. Your uniqueness is valued, welcomed, and appreciated here. We are dedicated to providing a positive workplace and base all employment decisions on your qualifications, performance, merits, as well as business needs. We are proud to be an Equal Employment Opportunity Employer. In addition to your base compensation, we offer a generous Total Rewards program which includes: Competitive salary Incentive Stock Option Plan Generous company 10% pension contribution regardless of employee contribution Cycle to work scheme Tax efficient technology schemes BUPA Private Healthcare Insurance once probationary period is successfully completed Unlimited PTO  subject to fair usage