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 looking for a Laser Characterization Engineer to join our Laser team. You will be the hands-on technical owner for bring-up, characterization, and validation of Lightmatter's laser modules and photonic systems — taking products from first-light through manufacturing qualification and production hand-off. You will work closely with controls engineers, photonics engineers, and the production team to translate module performance specifications into reproducible, manufacturable results. This is an individual-contributor role with direct ownership of  test plan development, characterization, bring-up and validation execution , and the data that drives module specifications. This role requires strong laboratory experience in integrated photonics and fiber optics, as well as expertise in photonics and electronics testing, and data analysis. Analytical skills, problem-solving, and the ability to clearly communicate and document your findings are essential. Responsibilities • Lead optical performance optimization (OPO) and initial bring-up for Guide ™ Laser  modules; define and execute bring-up sequences from unpowered to full operating condition. • Develop and own the bringup-to-eVT hand-off package: measurement summary, pass/fail criteria, and known-good reference data. • Own characterization campaigns involving Guide and Passage based optical links, including end-to-end link validation, channel optimization, and margin verification through the lens of Laser/Guide systems. Identify and operate to resolve link-level anomalies; close the loop with module-level root-cause analysis. • Develop structured manufacturing and characterization test plans aligned to photonics-control specs; define measurement protocols, calibration sequences, and acceptance criteria. Collaborate with control engineers to ensure test plan data supports algorithm validation and production deployment. • Write and maintain Python or MATLAB measurement automation scripts for optical, electrical, and thermal test sequences; build data pipelines to surface yield signatures and process trends. • Author clear characterization reports capturing methodology, results, and recommendations; communicate findings to cross-functional stakeholders. • Partner with the team on laser-safety interlock validation and controller characterization flows. • Interface with production on test plan deployment, NPI transitions, and manufacturing scale-up. • Experience with high-speed and optical link characterization methodologies is a plus. Required Qualifications • BS + 8 years, MS + 6 years, or PhD + 3 years in Electrical Engineering, Physics, Optical Engineering, Photonics, or a closely related field. • Hands-on experience characterizing laser modules (DFB lasers, optical amplifiers, and other coherent sources) in a research or NPI environment with experience with DWDM optical link bring-up and validation as a plus. • Proficiency with core photonics lab equipment: optical spectrum analyzers (OSA), optical power meters, lightwave component analyzers (LCA), high-bandwidth oscilloscopes, and signal generators. • Experience building or executing structured test plans for optical or electro-optic assemblies — from test design through data delivery. • Proficiency with Python or MATLAB scripting for measurement automation and statistical data analysis. • Strong written communication skills; able to produce thorough, well-organized characterization reports. • Familiarity with statistical process control (SPC), gauge R&R, or JMP for production yield analysis. Preferred Qualifications • Experience with laser module NPI, EVT, or manufacturing bring-up workflows; familiarity with hand-off packages to production. • Background in TEC/thermal control loops, laser safety interlock systems, or photonics control-style calibration flows. • Exposure to silicon photonics–III-V heterogeneous integration (bonded DFB sources, SOA, or hybrid photonic packages). • Familiarity with optical link budgets and system-level characterization; experience operating multi-channel photonic integration platforms. We offer competitive compensation. The base salary range for this role determined based on location, experience, educational background, and market data. Salary Range: total compensation goes beyond base salary, it also includes a new hire equity grant, annual performance-based equity, and other rewards that recognize your impact and contribution. $187,000—$240,000 USD Benefits • Comprehensive Health Care Plan (Medical, Dental & Vision) • Retirement Savings Matching Program • Life Insurance (Basic, Voluntary & AD&D) • Generous Time Off (Vacation, Sick & Public Holidays) • Paid Family Leave • Short Term & Long Term Disability • Training & Development • Commuter Benefits • Flexible, hybrid workplace model • Equity grants (applicable to full-time employees) Benefits eligibility may vary depending on your employment status and location. Lightmatter recruits, employs, trains, compensates, and promotes regardless of race, religion, color, national origin, sex, disability, age, veteran status, and other protected status as required by applicable law. Export Control Candidates should have capacity to comply with the federally mandated requirements of U.S. export control laws.