Staff/Principal Thermal Engineer

About the Company
Xscape Photonics is a cutting-edge technology company developing advanced photonic systems for high- performance computing and communication applications. Our work focuses on enabling next-generation optical interconnects through innovative integration of photonics, electronics, and packaging technologies.
We are building highly efficient, scalable solutions where thermal management plays a critical role in performance, reliability, and product success.
We are seeking a Staff or Principal Thermal Engineer to own thermal architecture, performance, and strategy for our photonic and electronic systems — from early concept through production. This is a high- ownership role: you will set the thermal design direction across programs, own module thermal performance against target temperature and crosstalk limits, lead the development of cooling solutions
(TECs, TIMs, heat spreaders/heat sinks, air and liquid cooling), drive simulation and validation methodology, and own thermal-related failure analysis. You will represent thermal engineering in customer- and leadership-facing technical reviews, work closely with optical, mechanical, electrical, packaging, firmware, and reliability engineers, and mentor and guide other thermal engineers as the team scales.

Key Responsibilities
Thermal Design & Analysis
• Own thermal architecture and strategy for photonic modules and systems across multiple programs, from concept through production
• Lead design and development of cooling solutions using:
◦ Thermoelectric coolers (TECs)
◦ Thermal interface materials (TIMs)
◦ Heat spreaders and heat sinks
◦ Air cooling and liquid cooling approaches
• Perform thermal trade-off analysis across candidate designs, evaluating cost, power consumption, and mechanical and electrical complexity to guide architecture decisions
• Lead critical cooling-technology, material, and supplier decisions (TECs, TIMs, cooling solutions), balancing product performance, cost structure, and long-term scalability
• Set thermal simulation methodology and standards; drive CFD analysis strategy (temperature distribution, heat flow, thermal crosstalk) and review the work of other engineers
• Define and own the thermal test and validation strategy, including instrumentation
(thermocouples, IR imaging, DAQ/LabVIEW) and test-to-simulation correlation
Thermal Failure Analysis
• Own thermal-related failure analysis, working closely with the Lead FA Engineer on the overall FA process
• Diagnose thermal-stack failure modes such as TIM pump-out and dry-out, solder void growth, bond-line degradation, TEC fatigue over thermal cycling, and warpage-driven loss of contact
• Apply thermal FA diagnostic techniques — IR/lock-in thermography for hot-spot localization, thermal transient testing and structure-function analysis, and coordination of CT/acoustic microscopy for interface defect detection
• Feed FA findings back into design margin, TIM/material selection, and thermal qualification criteria to prevent recurrence
Cross-Functional Leadership
• Own accountability for module thermal performance against targets — define the thermal budget, junction and case temperature limits, TEC/laser operating windows, and allowable thermal

crosstalk, and hold the design to them from prototype through production and across the product & operating life
• Own thermal integrity of the system, including thermal runaway prevention, heat-path optimization, and definition and enforcement of worst-case operating margins and guard-bands across environmental and use-case variations
• Represent thermal engineering in customer and executive/leadership reviews; present thermal compliance, risk, and trade-offs at program milestones
• Partner with mechanical, PCB, and packaging engineering to integrate thermal requirements early in design
• Support new product introduction (NPI) and transfer to manufacturing, including design for manufacturability and production ramp — working with contract manufacturers and assembly teams on TIM application, reflow, and thermal-stack assembly processes to ensure thermal performance holds in volume production
• Mentor and provide technical guidance to junior and mid-level thermal engineers; may directly or indirectly lead a small thermal team as it scales
• Own thermal risk assessment, design reviews, and technical documentation across programs
Required Qualifications
• Masters or PhD in Mechanical Engineering, Aerospace Engineering, or a related field, with a focus on heat transfer and fluid mechanics
• 8+ years of thermal engineering experience for Staff, or 12+ years for Principal (PhD + 5+ years of industry experience may be considered equivalent to MS + 8+ years for Staff-level scope)
• Demonstrated track record designing and delivering cooling solutions using TECs, TIMs, heat spreaders/heat sinks, and air and liquid cooling
• Deep CFD simulation expertise (e.g., Ansys Icepak/Fluent, Ansys Mechanical, or equivalent) with a record of setting simulation strategy, not only executing models
• Extensive hands-on thermal test and validation experience (IR imaging, thermocouples, DAQ systems) with demonstrated test-to-simulation correlation
• Demonstrated root-cause problem solving and thermal failure analysis, including experience diagnosing thermal-stack failure modes and applying thermal diagnostic techniques (e.g., IR/lock- in thermography, thermal transient testing)
• Experience owning thermal architecture at the system or program level, not solely at the component level
• Strong teamwork and cross-functional collaboration skills, with the ability to work effectively alongside optical, mechanical, electrical, packaging, firmware, and reliability engineers
• Excellent written and verbal communication skills, including the ability to present complex thermal analyses and trade-offs clearly to both technical and non-technical audiences
• This is a full-time, on-site role based in Santa Clara, CA
Preferred Skills
• Experience in photonics, optical transceivers, or high-density electronics packaging
• Experience with vapor chamber thermal design for high power-density, space-constrained applications
• Experience presenting thermal compliance and risk directly to customers or executive leadership
• Prior mentorship or direct/indirect leadership of other thermal engineers
• Programming and data analysis skills (Python, MATLAB) for test automation and data processing
• Experience with qualification/certification test campaigns and thermal reliability of materials and interfaces

What We Offer
• Ownership of thermal strategy on advanced photonics systems at the ground floor of a fast- scaling startup
• Collaborative and innovative work environment with direct access to leadership
• Competitive salary, equity, and benefits
• Career growth in a rapidly evolving technology space