Senior Embedded Engineer (RTOS)

Our accelerator is hardware that has never existed before, and it only becomes a product when software can drive it reliably at the lowest levels of the stack. Lumai is moving from evaluation systems to production, which puts the firmware, drivers and real-time control software underneath on the critical path. This hire is what makes the hardware dependable.

You will own the embedded software that brings Lumai's accelerator to life. You will write and maintain device drivers for Linux kernel and bare-metal environments, firmware for the control and management processors that sit alongside the main accelerator die, and the RTOS-based control tasks that keep the system deterministic. You will take new hardware revisions through bring-up, from clock tree and interrupt routing to the first boot.

What is genuinely hard about this is that you are working on custom silicon with no reference design underneath you. When the hardware and the driver disagree, there is no support forum to consult: you are the person who finds out which one is wrong, with JTAG, a scope and a logic analyser, and then makes it reproducible for everyone else.

By month six, you will have taken at least one new hardware revision through bring-up to a stable boot, put the embedded team's coding standards, review practice and test methodology in place, and had the driver stack running against a production configuration.

• Develop and maintain device drivers for Lumai's accelerator across Linux kernel and bare-metal environments.

• Write and debug firmware for the control and management processors alongside the main accelerator die.

• Lead board support package bring-up on new hardware revisions: clock tree, interrupt routing, peripheral initialisation.

• Implement RTOS-based control tasks with deterministic scheduling and safe resource management.

• Validate bring-up with hardware engineers using JTAG debugging, oscilloscope analysis and logic capture.

• Set the coding standards, review practice and testing methodology for the embedded team

Must-have

• Five or more years of embedded software in C/C++ on production hardware (a degree in electrical or computer engineering, or equivalent experience).

• Proven experience writing Linux device drivers: character, platform or PCIe.

• Hands-on board support package bring-up on custom hardware, from schematic review to first OS boot.

• A solid grasp of RTOS concepts: task scheduling, inter-task communication, memory protection.

• Proficiency with hardware debug tools: JTAG/SWD debuggers, oscilloscopes and logic analysers.

Strong preference for

• PCIe driver development or DMA engine programming.

• Power management frameworks such as ACPI or Linux PM runtime.

• Prior work on AI accelerator or GPU driver development.

Lumai is the optical compute company building the next generation of AI infrastructure. Spun out of optics research at the University of Oxford in 2021, we compute with light instead of electrons. Our 3D optical technology carries out the matrix multiplications at the heart of AI inside beams of light travelling through free space, which lets it go beyond the limits of both silicon GPUs and integrated photonics.

In April 2026 we launched Iris Nova, the world's first optical computing system to run billion-parameter large language models in real time, using up to 90% less energy than conventional GPU-based systems. Iris Nova, the first server in the family, is now available for evaluation by hyperscalers, neoclouds, enterprises and research institutions. Aura and Tetra will follow.

Our work won the Falling Walls Award for Science Breakthrough of the Year 2025 and 'Best Overall Technology' at the OCP Future Technologies Symposium. We are headquartered in Oxford.

You'll work on a new kind of computer. Optical computing for AI has been promised for decades. We have a working system running real models, and the hard part left is taking it to volume.

Your work ships. We are moving from first product to volume production, so what you build this year goes into the servers our customers run.

You'll work across disciplines. Optical engineers, machine learning researchers, and hardware and software engineers solve problems together. You will learn things that don't appear on your job description.

The work matters beyond Lumai. AI's appetite for energy is one of the defining constraints of the next decade. Our mission is sustainable intelligence at global scale: AI that is faster, cheaper to run and far less power-hungry.

You'll join early. You'll have a real say in how we build the product, the team and the way we work.

Lumai is an equal opportunity employer. We make hiring decisions based on skills, experience and potential, and we welcome applications from people of all backgrounds. If you need an adjustment at any stage of the hiring process, let us know and we will do our best to support you.