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Salary: USD 212,000 - 320,000 / annual
Lightmatter is revolutionizing AI data center infrastructure through photonics technology. The company recently raised $400M in Series D funding at a $4.4B valuation and is scaling rapidly across all departments.
You will own the end-to-end design of high-power laser epitaxial structures and laser devices—including DFB, DBR, and external-cavity architectures—for Lightmatter's integrated, scalable laser solutions powering AI communications and computation. This is a senior technical anchor role where you will drive designs from epitaxial layer stack through cavity and device architecture, working closely with cross-disciplinary teams internally and across manufacturing partners to translate system requirements into robust, manufacturable, high-reliability hardware.
Key responsibilities include:
- Design high-power laser epitaxial structures 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 for target output power, wavelength control, narrow linewidth, high side-mode suppression ratio (SMSR), low relative intensity noise (RIN), and 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, translating system needs into detailed device designs
- Partner with characterization teams to define test beds, map L-I-V curves and thermal coefficients back to design parameters, and iterate to close performance gaps
- Collaborate across systems, electrical, packaging, and thermal engineering to define component-level specs, 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
- Serve as an internal subject-matter expert and thought leader; mentor engineers, review designs, and contribute to the laser technology roadmap
- Publish and present novel ideas at premier photonics conferences
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 operate as a recognized internal subject-matter expert. Creativity, analytical rigor, and clear communication are essential.
**Requirements:**
- Ph.D. in Photonics, Electrical Engineering, Applied Physics, Materials Science, or related discipline with at least 5 years of relevant post-degree experience; OR M.S. with at least 8 years of relevant experience; OR equivalent experience
- Deep, hands-on expertise in semiconductor laser and epitaxy design for III-V compound semiconductor devices
- Proven track record designing DFB, DBR, and/or external-cavity lasers
- Strong grounding in laser physics and semiconductor device physics (optical gain, threshold, slope efficiency, RIN, linewidth, thermal rollover, back-reflection behavior)
- Proficiency with physics-based laser and photonic device simulation tools (e.g., PhotonDesign Harold/PICWave, VPIphotonics, Lumerical, or equivalent) and data analysis in Python
- Demonstrated ability to independently own complex designs spanning multiple programs and resolve critical, ambiguous technical issues as a recognized subject-matter expert
- Track record of close collaboration with characterization/test teams and cross-functional hardware teams
- Ability to convey complex technical concepts to both technical and non-technical stakeholders with strong, clear communication
**Preferred Qualifications:**
- Experience with silicon photonics and heterogeneous integration of III-V gain material on silicon
- Experience designing semiconductor optical amplifiers (SOAs)
- Experience with high-power semiconductor lasers for datacom applications
- Experience maturing a laser product from prototype through high-volume manufacturing, including epi growth and reliability qualification
- Record of publishing novel photonics results and engaging with the broader optics community
- Self-starter with "no task is too big or small" attitude and ability to learn quickly
