Principal Engineer Silicon Photonics

Lumilens•San Jose, CA

About The Position

At Lumilens we are building the critical photonics infrastructure that powers tomorrow’s AI supercomputing. From chip-to-chip optical interconnects to scalable photonic engines, Lumilens is unlocking a new era of computing, faster, cooler, and massively more efficient. Lumilens is a well-funded startup backed by Mayfield and led by veterans who’ve built and scaled some of the most transformative technologies in the industry. This isn’t incremental innovation, it’s a ground-floor opportunity to rethink the optical layer from the silicon up. You’ll work alongside a team of world-class engineers solving some of the hardest challenges in optics, systems, and scale. Every line of code, every design decision, every breakthrough you help deliver will shape the infrastructure of tomorrow. If you're looking for mission, momentum, and the chance to make an outsized impact jump on the rocket ship. We’re just getting started. POSITION OVERVIEW We are seeking a Principal Engineer, Silicon Photonics to join our rapidly growing team. This is a high-impact leadership role for someone who can shape product direction, translate customer needs into clear technical requirements, and drive cross-functional execution from concept through validation. The ideal candidate brings deep experience with packaged silicon photonics, including optical engine integration, assembly flows, and manufacturing considerations for next-generation optical interconnect products. The successful candidate will work closely with customers, contract manufacturers, suppliers, and internal development teams to meet product objectives while instilling a culture of quality, accountability, and continuous improvement.

Requirements

Proven experience in a principal-level technical leadership role developing and delivering photonics-based products.
Deep expertise in silicon photonics design, performance characteristics, and trade-offs.
Direct experience with packaged silicon photonics or optical engine development, including packaging trade-offs, integration constraints, and manufacturing considerations.
Demonstrated ability to perform optical link budget analysis using simulation and modeling.
Experience defining product requirements and driving execution across hardware, firmware, software, validation, and manufacturing teams.
Experience defining test plans (EVT, DVT, SVT) and test methodologies for optical systems.
Ability to work effectively and drive decisions within a fast-paced, startup environment.
Must be hands-on in a lab environment.

Nice To Haves

Experience with test automation frameworks and scripting (e.g., Python).
Direct experience working with hyperscale data center customers or suppliers on packaged optics, co-packaged optics, or optical I/O solutions.
Experience with fiber attach technologies, optical assembly processes, and package-level integration challenges for silicon photonics products.

Responsibilities

Lead Product Definition: Own and drive product requirements for next-generation optical interconnects, balancing performance, manufacturability, cost, power, and time-to-market.
Be the Customer and Product Voice: Serve as the primary technical interface with customers, foundry partners, and suppliers, ensuring product decisions are grounded in real-world use cases, market needs, and execution realities.
Drive Cross-Functional Alignment: Create and own clear product requirements, aligning internal engineering teams, external partners, and key stakeholders around priorities, trade-offs, milestones, and deliverables for packaged optics solutions.
Analyze and Optimize: Perform critical link analysis, using simulation and modeling to assess impairments like noise and distortion, ensuring our products deliver robust performance in real-world systems.
Translate System Goals into Execution: Convert top-level product objectives into actionable requirements for silicon photonics, electronics, firmware, software, validation, and manufacturing partners.
Lead Packaged Optics Execution: Guide the development of packaged silicon photonics solutions, including co-packaged optics and optical I/O approaches, with attention to assembly tolerances, fiber attach, thermal constraints, test strategy, reliability, and scale-up readiness.
Validate: Define the complete testing strategy, from engineering verification and product validation to system integration. You will define test methodologies, select equipment, and be hands-on in the lab to bring our products to life.