Sr Staff/Principal Laser Design Engineer

Lightmatter is leading the revolution in AI data center infrastructure, enabling the next giant leaps in human progress. The company invented the world’s first 3D-stacked photonics engine, Passage™, capable of connecting thousands to millions of processors at the speed of light in extreme-scale data centers for the most advanced AI and HPC workloads.

Lightmatter raised $400 million in its Series D round, reaching a valuation of $4.4 billion. We will continue to accelerate the development of data center photonics and grow every department at Lightmatter!

If you're passionate about tackling complex challenges, making an impact, and being an expert in your craft, join our team of brilliant scientists, engineers, and accomplished industry leaders.

Lightmatter is (re)inventing the future of computing with light!

We are hiring a Laser Design Engineer to join our laser module development team. In this role, you will own the design of high-power laser epitaxy and laser devices—including DFB, DBR, and external-cavity architectures—for Lightmatter’s integrated and highly scalable laser solutions for AI communications and computation. You will drive designs from epitaxial layer stack through cavity and device architecture, working closely with colleagues and cross-disciplinary engineering teams internally and across our ecosystem of manufacturing partners to translate system requirements into robust, manufacturable, high-reliability hardware.

This role requires deep expertise in semiconductor laser and epitaxy design, a strong command of laser and semiconductor device physics, and the judgment to navigate the design space of performance, schedule, reliability, power consumption, and cost. As a senior technical anchor, you will plan and execute across multiple concurrent programs, resolve critical and often ambiguous technical challenges with limited oversight, develop new methods and design approaches, and serve as a recognized internal subject-matter expert. Creativity, analytical rigor, and clear communication are essential.

Join a tight-knit team where each individual’s contributions directly influence the success of the company and product. You’ll have the opportunity to build innovative laser solutions from the ground up and tackle groundbreaking challenges. Work with people who love to build and who thrive in diverse technical environments where great ideas are prioritized.

Responsibilities

Own the design of high-power laser epitaxial structures and laser devices—including DFB, DBR, and external-cavity architectures.

Design epitaxial layer stacks in III-V material systems, optimizing for optical gain, carrier confinement, threshold current density, wall-plug efficiency, and high-temperature performance.

Optimize laser cavity designs to achieve target output power, precise wavelength control, narrow linewidth, high side-mode suppression ratio (SMSR), low relative intensity noise (RIN), and robust back-reflection tolerance.

Contribute to monolithic and silicon-photonics heterogeneously integrated laser and semiconductor optical amplifier (SOA) development.

Use physics-based and traveling-wave simulation tools to model heterostructure and cavity behavior, spectral response, and tuning, translating high-level system needs into detailed device designs.

Partner with the characterization team to define test beds and map measured L-I-V curves, near-/far-field profiles, thermal coefficients, and linewidth back to design parameters, iterating to close performance gaps.

Collaborate across disciplines—systems, analog/electrical, packaging, and thermal engineering—to define component-level specs derived from link budgets, co-design drivers and submounts, and define optical coupling and thermal-management strategies.

Work with epitaxy and foundry vendors to specify, qualify, and transfer designs into volume manufacturing.

Act as an internal subject-matter expert and thought leader on laser device and epi design; …