Senior HW Engineer – PCB Analog Design

At the centre of an optical computer sits a set of circuits that have to read, drive and hold steady some very small, very fast signals: photodetector front ends, laser and modulator drives, precision converter interfaces, and the quiet power and references underneath them. This role owns them, at board level, from the optical requirement through to the production build.

You will design the board-level analog and mixed-signal circuits that connect our electronics to light, and take them the whole way: specification, simulation, layout guidance, lab bring-up, characterisation and production. You will agree the optical requirements - optical power budgets, bandwidth, noise, linearity - with the photonics and system teams, and turn them into analog architectures and circuit specifications.

What is genuinely hard about it is working at the boundary between optics, mixed-signal and high-speed digital, where noise budgets are tight and the measurement is as demanding as the design. A microvolt-level front end does not care that the same board carries high-current switching rails; getting both right on one stackup is the job.

By month six, you will have characterised at least one full analog subsystem on the bench, correlated it with simulation across corners, and put the layout constraints and test procedures in place that other engineers can follow.

• Design board-level analog and mixed-signal circuits: photodiode front ends, TIAs, ADC/DAC driver and reconstruction stages, laser drivers, modulator drivers and bias networks.

• Translate photonic system requirements into analog specifications and architectures with the photonics and system teams.

• Design low-noise power delivery for sensitive circuits: LDO post-regulation, filtering, precision voltage and current references, grounding and partitioning schemes.

• Design control loops and precision circuits for photonic components: TEC and temperature control, laser current control, monitor photodiode readout and heater drivers.

• Run circuit simulation and analysis (SPICE, noise, stability, worst-case, Monte Carlo) and confirm designs meet performance across corners.

• Give placement, routing and grounding guidance to the layout engineer, review layouts for analog integrity, and select and qualify analog components through to production.

• Lead lab bring-up and characterisation of analog circuits - noise, bandwidth, linearity, stability, crosstalk - and correlate the results with simulation.

• Work with the ASIC team on chip-to-board analog interfaces, including on-chip versus off-chip analog partitioning.

Must-have

• A degree in electronic engineering or a related discipline, plus extensive experience designing analog and mixed-signal circuits at board level for products that reached production.

• Strong analog fundamentals covering op-amp and amplifier design, feedback and stability, noise analysis, filtering and precision circuit design.

• Hands-on experience designing TIAs or other low-noise, high-bandwidth amplifier front ends.

• Experience interfacing high-performance ADCs and DACs, including driver design, anti-aliasing and reconstruction filtering, clocking sensitivity and reference design.

• Solid knowledge of low-noise power supply design, grounding, shielding and mixed-signal partitioning.

Strong preference for

• SPICE-based simulation (LTspice, Cadence PSpice/Spectre, TINA or equivalent) and schematic capture in Cadence OrCAD/Allegro or Altium.

• Bench characterisation with oscilloscopes, spectrum and network analysers and precision source-measure equipment, and low-noise measurement technique.

• Writing layout constraints for sensitive analog circuits and reviewing layouts critically.

• Photonic or optoelectronic systems: photodetector receivers, laser diode drivers, optical modulator drivers or optical transceivers.

• Mentoring other engineers in analog design practice.

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.