Laser Characterization, Temp

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! As a Laser Characterization Intern, you will focus on the fundamental performance, physics, and characterization of the semiconductor laser sources that power our photonic computing architecture. You will be responsible for executing State-of-the-Art (SOA) laser testing to ensure the highest levels of spectral purity and stability. Responsibilities Perform hands-on characterization of semiconductor lasers, laser sources, and semiconductor optical amplifiers. Measure and analyze laser and SOA performance metrics, including output power, wavelength, optical spectrum, side-mode suppression ratio, relative intensity noise, gain, saturation behavior, and wavelength/power stability. Conduct LIV measurements and evaluate laser behavior across current, voltage, temperature, and operating conditions. Perform wavelength and optical power stability measurements over time and across temperature. Characterize optical spectra using optical spectrum analyzers and related optical test equipment. Support RIN, SMSR, optical power, wavelength tuning, and stability measurements. Operate optical lab equipment such as current drivers, temperature controllers, optical spectrum analyzers, optical power meters, photodetectors, polarization controllers, optical filters, optical switches, and fiber-coupled optical components. Develop Python-based automation scripts for instrument control, data collection, data processing, and measurement reporting. Analyze measurement data, identify trends or anomalies, and summarize results clearly for the engineering team. Work closely with photonics, laser, packaging, and characterization teams to support laser and SOA bring-up, debug, and validation activities. Qualifications Currently enrolled in a PhD or advanced degree program in Electrical Engineering, Physics, Applied Physics, Photonics, Optics, or a related field. Strong understanding of semiconductor lasers, laser physics, and basic semiconductor physics. Familiarity with laser characterization concepts such as LIV curves, threshold current, slope efficiency, wall-plug efficiency, wavelength tuning, linewidth, RIN, SMSR, optical spectrum, and power stability. Hands-on experience with optical lab measurements and optical test equipment. Good understanding of semiconductor optical amplifiers, including optical gain, saturation power, noise, and wavelength-dependent behavior. Experience using optical instruments such as optical spectrum analyzers, optical power meters, current sources, temperature controllers, photodetectors, and optical filters. Exposure to Python scripting for instrument automation, data analysis, and visualization. Strong analytical and problem-solving skills for debugging open-ended lab and measurement issues. Ability to work independently in a lab environment and communicate results clearly Preferred Qualifications Prior experience characterizing DFB lasers, tunable lasers, laser diodes, or semiconductor optical amplifiers. Experience with RIN, SMSR, linewidth, wavelength stability, or long-term optical power stability measurements. Familiarity with fiber-optic alignment, polarization control, optical coupling, and optical loss budgeting