Optical Engineer - Optical Interconnects

CScale is building the interconnect for gigawatt-scale AI. As AI scale-up moves toward deployments spanning thousands of accelerators and dozens of racks, the network needs to deliver high bandwidth, predictable low latency, and continuous communication. CScale is building integrated optical interconnect designed for this new scale, enabling accelerators to work together like a single, much larger computer. But at this scale, performance is only part of the challenge. Optical failures are inevitable, and the system needs to keep running. CScale is designing the interconnect for continuity. Lasers will fail. Compute shouldn’t. The ambition is simple: Build AI interconnect you can take for granted. CScale came out of stealth in September 2026 with $145 million in Series C funding, bringing total funding to $188 million.

We are seeking an Optical Engineer to take technical ownership of optical subsystems connecting lasers, photonic integrated circuits (PICs), and fiber arrays, with a focus on free-space optical coupling. You will drive development from requirements and architecture through optical design, integration, validation, qualification, and high-volume manufacturing.

This role offers broad scope across the optical system. You will define / improve optical architectures and performance budgets, evaluate design trade-offs, shape component and interface requirements, and lead the integration and validation of complete optical subsystems. Working closely with laser, PIC, electrical, mechanical, thermal, packaging, test, and manufacturing teams, you will contribute to broader product architecture and translate system requirements into practical, production-ready designs.

This is a hands-on role in a startup environment. You will move between modeling, laboratory development, packaging and alignment work, supplier engagement, and production problem-solving. Your responsibility extends through manufacturing ramp, with success measured by optical performance, reliability, manufacturing yield, throughput, and cost at volume.

Key Responsibilities

Optical Architecture and System Requirements

• Own the optical subsystem architecture across laser delivery, PIC coupling, free-space optical elements, and fiber-array interfaces. Evaluate architecture alternatives and contribute to product-level decisions affecting performance, integration, and scalability.
• Translate product requirements into design target, manufacturing spec, interface definitions, and operating margins. Address coupling efficiency, polarization, wavelength dependence, reflections and optical feedback, channel uniformity, crosstalk, and thermal stability as applicable.
• Lead design trade-offs across optical performance, size, thermal behavior, alignment tolerance, reliability, assembly complexity, production throughput, and cost. Document decisions and validate the assumptions behind them.
• Work with laser and PIC designers, and packaging engineers to define source characteristics, optical modes, coupling structures, channel geometry, and interface requirements that support the overall optical architecture.
• Work with global team extending into 4 different time zones as a joint effort driving forward product development.

Integration, Validation, and Reliability

• Build, align, characterize, and debug prototypes and integrated optical assemblies. Lead investigation of performance limitations across the complete optical path.
• Collaborate with mechanical, thermal, and packaging engineers on optical datums, component placement, alignment strategies, attachment methods, and assembly sequences. Address bonding-induced shifts, thermomechanical drift, stress, and contamination risks.
• Own optical verification plans, measurement methods, and acceptance criteria. Validate performance across channels, wavelengths, operating conditions, and expected component and assembly variation.
• Work with system and electrical teams to connect optical measurements to overall link performance and operating margins.
• Partner with reliability engineers to define relevant qualification conditions, evaluate optical stability and degradation, and close failure mechanisms through design or process improvements.

High-Volume Manufacturing and Production Delivery

• Incorporate manufacturability, assembly automation, and testability into the architecture and design process. Develop active, passive, or hybrid alignment approaches with packaging, process, and automation teams.
• Define optical assembly tolerances, process windows, metrology requirements, and production test coverage. Establish acceptance limits and ensure measurement repeatability, reproducibility, and correlation between development and factory test.
• Drive optical readiness for pilot builds, qualification, and production ramp. Use experimental and statistical data to improve yield, channel consistency, alignment and test cycle times, throughput, and unit cost.
• Work with manufacturing partners to convert optical designs into repeatable assembly and test processes. Resolve optical performance issues across component lots, equipment, and production conditions.
• Release and maintain optical specifications, interface definitions, tolerance budgets, test procedures, and validation reports. Support controlled design and process changes, including assessment of their impact on performance and qualification.
• Maintain technical ownership of optical performance through production ramp and sustained manufacturing, using production and field data to guide corrective actions and future designs.

Technical Leadership and Collaboration

• Serve as the technical owner for the optical subsystem, aligning cross-functional teams around requirements, design decisions, development milestones, and risk mitigation.
• Work directly with optical component suppliers and manufacturing partners to establish specifications, evaluate capabilities, qualify components and processes, and resolve technical issues.
• Communicate trade-offs and recommendations clearly through design reviews, technical documentation, and data-driven discussions.
• Contribute to future optical architectures and product roadmaps based on system needs, technology opportunities, and lessons from manufacturing.

Qualifications

• Ph.D. preferred in Optical Engineering, Physics, Electrical Engineering, or a related field, or equivalent practical experience.
• Strong understanding of free-space optics, laser beam propagation, Gaussian optics, fiber and waveguide mode coupling, polarization, and optical tolerancing.
• Demonstrated experience designing, integrating, and validating optical subsystems involving lasers, photonic devices, precision optics, or fiber coupling.
• Ability to translate system requirements into optical architectures, component specifications, performance budgets, and measurable validation criteria.
• Proficiency with relevant optical design and simulation tools, such as Zemax OpticStudio, CODE V, or equivalent, and programming or analysis tools such as Python or MATLAB.
• Strong hands-on skills in optical alignment, characterization, test development, and systematic troubleshooting.
• Experience bringing optical hardware into production, including involvement in manufacturing transfer, pilot builds, qualification, or production yield improvement.
• Ability to evaluate optical performance in the context of mechanical tolerances, thermal behavior, materials, assembly processes, and reliability.
• Strong technical ownership and cross-functional communication, with the flexibility to address both system-level decisions and detailed implementation challenges in a startup environment.
• Experience delivering optical interconnects, photonic engines, optical transceivers, laser modules, or related precision optical products into high-volume manufacturing.
• Experience with multichannel laser-to-PIC or PIC-to-fiber-array coupling, silicon photonics, or other integrated photonic platforms.
• Experience with automated optical alignment, passive alignment features, machine vision, precision assembly, or production optical testing.
• Familiarity with design of experiments, measurement system analysis, statistical process control, and structured failure analysis.
• Experience working with optical component suppliers, equipment vendors, and contract manufacturing partners.
• A record of leading technical decisions across disciplines and carrying those decisions through implementation and production.

What Success Looks Like

• A well-defined optical architecture with clear interface requirements, validated performance budgets, and documented design decisions.
• Integrated optical hardware that meets performance and reliability requirements across operating conditions and expected manufacturing variation.
• Correlated models and measurements that explain performance, identify sensitivities, and support predictable design improvements.
• Qualified assembly and test processes that meet agreed yield, throughput, cycle-time, and cost targets.
• Successful delivery from prototypes through pilot builds into sustained high-volume production, with optical issues resolved and improvements carried into subsequent product generations.

Compensation includes a base salary of $150,000–$250,000 and equity in CScale. Final offers depend on experience, market conditions and location.