Quantum Communication System Developer

About us

Xen Quantum is building next-generation quantum communication systems based on silicon photonics and a patented architecture, enabling practical and scalable quantum key distribution (QKD). Our technology simplifies implementation and lays the foundation for high-volume manufacturing and real-world deployment.

Position Overview

We're looking for a Quantum Communication System Developer to join as one of our first technical hires and play a defining role in shaping both our technology and the engineering culture.
This is a hands-on role at the intersection of quantum optics, photonics, cryptography and system engineering - spanning laboratory development, system integration, and early field deployment with customers.

What You'll Do

• Develop, integrate, and characterise quantum key distribution (QKD) systems, with a focus on optical subsystems and protocol execution
• Design, test, and evaluate photonic integrated circuits (PICs) for quantum communication applications
• Build and characterise optical and electro-optic subsystems and prototypes
• Analyse experimental data and feed results back into system and product design
• Design and execute experiments, pilot trials, and early customer deployments
• Work closely with founders and collaborators to develop deployable systems

What We're Looking For

Education & Experience

• MSc or PhD in Physics, Engineering, or a closely related field
• Demonstrated excellence in experimental quantum optics and optical communications
• At least 3 years of hands-on laboratory experience in relevant topics
• Proven ability to design, build, and characterise optical systems independently

Technical Skills

• Hands-on experience with optical system construction and characterisation
• Fibre-optic systems experience (lasers, modulators, detectors, fibre components)
• Electro-optic lab experience, including familiarity with RF signals and measurements
• Experience building, characterising, and controlling QKD systems
• Scientific programming experience (Python and relevant libraries; C/C++ highly valued)
• Experience with Linux-based systems and version control (git)
• Statistical data analysis and visualisation
• Experience with numerical modelling and simulations
• Strong project management and self-organisation skills, independently planning and executing work while reliably meeting timelines, technical milestones, and other constraints

Nice to Have

• Experience with photonic integrated circuit design and characterisation
• Experience with field trials or deployed optical systems
• Exposure to customer-facing technical work

This is a wish list, not a requirements list – if you have a technical background, are excited about what we're building and want to be part of an early-stage start-up, we want to hear from you.

How You Work

• Strong communication and collaboration skills
• Creative and flexible problem-solver, able to work around real-world constraints
• Comfortable operating independently in an early-stage environment
• Willing to take ownership of the responsibilities associated with the role, and help define the technology development

Compensation & Benefits

• £40,000 – £60,000 pa, depending on experience
• Company shares options plan
• Enhanced annual leave (25 days + bank holidays)
• Primarily in-person working (in Cambridge, UK), with flexible options where possible
• Early-hire role with genuine scope to grow with – and help shape - the business